Absorbent article with function-formed topsheet, and method for manufacturing

ABSTRACT

An absorbent article in the form of a feminine hygiene pad is disclosed. The article includes a topsheet formed of a section of formed nonwoven web material having an ordered arrangement of zones, each zone comprising one or more attenuated regions adjacent to one or more built-up regions, wherein the attenuated regions have a first average basis weight and the built-up regions have a second average basis weight. Through configuration of the regions and the ordered arrangement, inclusion of melt additive to the resin(s) from which the filaments are spun and/or application of a surfactant to a surface of the topsheet, the topsheet may be imparted with a Rewet of no greater than 0.50 g and an Acquisition Time of no greater than 25 seconds, balancing competing topsheet performance characteristics in a manner acceptable or preferable for consumers/users.

FIELD OF THE INVENTION

The present disclose relates to disposable absorbent articles such asfeminine hygiene pads, and particularly articles and pads havingtopsheets having structural features formed therein.

BACKGROUND OF THE INVENTION

Wearable disposable absorbent articles such as feminine hygiene pads,adult incontinence pads and disposable diapers typically include atopsheet of material adapted to serve as the wearer-facing outer layerof an envelope structure that contains absorbent material. Typically thetopsheet is adapted to be liquid permeable such that liquid bodyexudates may pass therethrough, to reach the absorbent materialcontained in the envelope structure, and be absorbed and retained by theabsorbent material until the time the article is removed and discarded.Generally it is desired that the topsheet serve to readily receiveaqueous fluid such as urine or menstrual fluid, conduct the fluid in az-direction therethrough, and release or desorb it to an absorbentstructure disposed adjacently beneath the topsheet.

For combined purposes of cost effectiveness, wearer comfort andfunctionality, topsheets of many currently-marketed absorbent articlesare made of nonwoven web material formed in some portion, or entirely,of filaments spun from polymer resins. Through a number of technologiescurrently known, various types of nonwovens may be manufactured to havesufficient liquid permeability, suitably soft feel to the skin, andmechanical strength making them suitable for forming topsheets. Nonwovenweb materials (“nonwovens”) may be formed of synthetic fibers, such asbut not limited to fibers spun from polyolefins, polyesters, polyamides,etc., or combinations thereof. Nonwovens may be formed using variousprocesses that form a cohesive fabric-like web in which the fibers are“continuous” (of relatively long, variable and indefinite lengths) orstaple fibers (fibers cut into relatively short and substantiallyuniform lengths).

Various attempts have been made to make nonwovens used to form topsheetsvisually appealing to wearers/users, to impart them with an appearanceof having functionally beneficial attributes, and/or to impart them withactually functionally beneficial attributes. Such attempts have includedprinting with decorative or functionally suggestive print designs; orembossing and/or bonding to impart decorative, functionally suggestiveor even actually functional surface topographical features. Theseattempts involve transformations generally occurring downstream offormation of a batt of filaments, and have been of limited effect withrespect to imparting a perceivably dramatic set of three-dimensionaltopographical features and/or imparting beneficial functionality.Accordingly, there is room for improvement in cost-effective techniquesfor imparting three-dimensional structural features to nonwoven webmaterials to be used to make topsheets. Additionally, currentlyavailable absorbent articles with nonwoven topsheets have left room forimprovement in providing for rapid acceptance and movement of fluid downinto the absorbent structure following discharge, avoidance of fluidretention in the topsheet, and rewetting.

SUMMARY OF THE INVENTION

The invention is a feminine hygiene pad including a liquid permeabletopsheet and an absorbent structure disposed therebeneath, the topsheethaving features formed therein via a disposition of filaments that formattenuated regions adjacent to built-up regions according to an orderedarrangement. The attenuated regions have a first average basis weightand the built-up regions have a second average basis weight greater thanthe first average basis weight, the difference in basis weightscorresponding to disposition of the filaments according to the orderedarrangement. The ordered arrangement of attenuated regions and built-upregions may be configured in any number of patterns that enable thetopsheet in combination with a suitable absorbent structure to beimparted with a consumer-acceptable or preferred balance of Rewet nogreater than 0.5 g and an Acquisition Time no greater than 25 seconds.In some examples the balance may be facilitated via inclusion of ahydrophobizing melt additive in the resin(s) from which the filamentsare spun, which causes built-up regions to inhibit x-y directionmovement of fluid through the topsheet. In combination or alternatively,the balance may be facilitated via inclusion of hydrophilizingsurfactant applied to filaments proximate the absorbent-facing side ofthe topsheet, which causes the absorbent-facing side filaments to drawfluid in the z-direction from the wearer-facing side toward theabsorbent-facing side.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an example of an absorbent article in the formof a feminine hygiene pad.

FIG. 2 is a plan view of the pad of FIG. 1, shown with wing portionsturned under and thereby depicting an in-use wear-facing portion.

FIG. 3 is a schematic lateral cross section view of the pad of FIG. 1,taken along a lateral axis.

FIG. 4 is a schematic lateral cross section view of the pad with wingportions folded under as depicted in FIG. 2, taken along a lateral axis,shown associated with a crotch portion of a pair of underpants.

FIGS. 5A-5D are plan views of non-exclusive examples of topsheets ofvarious shapes.

FIG. 6 is a plan view of an example of a topsheet for an absorbentarticle in the form of a feminine hygiene pad.

FIG. 7 is a schematic lateral cross section of the topsheet of FIG. 6,taken along a lateral axis.

FIG. 8 is an expanded schematic view of the portion of the cross sectionidentified as “8” in FIG. 7.

FIG. 9 is an expanded schematic view of the portion of the topsheetidentified as “9” in FIG. 6.

FIG. 10 is a schematic lateral cross section of the portion of thetopsheet shown in FIG. 9.

FIG. 11 is a schematic side-view illustration of an example ofconfiguration of equipment for manufacturing a nonwoven web material.

FIG. 12 is a schematic plan view of an example of a portion of a formingbelt receiving side as it might appear with the belt disposed aboutguide/drive rollers.

FIG. 13 is an expanded schematic view of the portion of the forming beltreceiving side identified as “13” in FIG. 12.

FIG. 14 is a schematic lateral cross section of the portion of theforming belt shown in FIG. 13.

FIG. 15 is an expanded schematic view of the cross section of FIG. 14,illustrating the general directions of filament travel to, and air flowthrough, the forming belt when in operation.

FIG. 16 is a schematic lateral cross section view of filamentaccumulation on the portion of the forming belt as shown in FIG. 15,following deposition of filaments thereon to form a batt.

FIG. 17 is a schematic lateral cross section view of a batt of filamentsformed on the portion of a forming belt shown in FIG. 16, followingremoval therefrom.

FIGS. 18 and 19 are schematic plan views of examples of topsheets havingadditional examples of features formed according to the processesdescribed herein.

FIGS. 20 and 21 are schematic lateral cross-section views of portions ofexamples of topsheets formed of nonwoven web material, illustratingpresence of materials added to primary filament components.

FIG. 22 is a plan view of an example of a feminine hygiene pad with aconfiguration of a channel portion.

FIGS. 23A-23K are plan views of examples of configurations of channelportions for a topsheet.

FIGS. 24A-24E are plan views of examples of configurations of channelportions for a topsheet, shown with geometric references for determiningwhether the configurations predominately circumscribe a discharge locuson the topsheet.

FIG. 25 is a plan view of an example of a topsheet with a configurationof channel portions and hinge portions.

FIGS. 26A and 26B are grayscale reproductions of photographs of samplesof nonwoven web material having discrete low bulk portions, channelportions and built-up regions.

FIG. 27 is an enlarged view of the zone 160 identified in FIG. 26A.

FIG. 28 is an image of portion of a mask used to produce a forming beltused to make the nonwoven web material sample depicted in FIG. 26B, witha superimposed dimension scale indicator.

DESCRIPTION OF EXAMPLES Definitions

With respect to a nonwoven web material formed partially or entirely offibers and/or filaments, a “bond” is a three-dimensional zone within thematerial in which a plurality of the filaments are held together in aunitary mass created by one or a combination of a deposit of adhesiveapplied to the material, thermal fusing caused by localized applicationof heating energy to the material (for example, heat from definedbonding protrusions on a heated bonding roller, or ultrasonic vibratoryenergy from a sonotrode in combination with a bonding roller withdefined bonding protrusions), or plastic deformation and entanglement orintermeshing caused by localized application of pressure (for example,by a bonding roller with defined bonding protrusions) to the material inthe z-direction. A bond has a two-dimensional profile along the x-yplane approximated by the large surfaces of the web material, as well asa z-direction dimension. When bonds are created via use of a bondingroller with defined bonding protrusions, the two-dimensional profiles ofthe bonds will approximately reflect the shape(s) of the bondingprotrusions.

“Fiber” as used herein means an elongate particulate having a lengthless than 5.08 cm (2 in.). In the field of nonwoven web manufacturing,fibers are typically considered discontinuous in nature. Non-limitingexamples of fibers include natural fibers such as wood pulp, cotton andbamboo fibers, and synthetic staple fibers (which may be manufactured bychopping filaments) such as polypropylene, polyethylene, polyester,copolymers thereof, rayon, lyocell, glass fibers and polyvinyl alcoholfibers.

“Filament” as used herein means an elongate particulate having a lengthequal to or greater than 5.08 cm (2 in.). In the field of nonwoven webmanufacturing, filaments are typically considered to be of indefinitelength and/or be substantially continuous in nature with respect tononwoven web materials in which they appear, in contrast to fibers, itbeing recognized that they cannot be of infinite length. Non-limitingexamples of filaments include meltblown and/or spunbond filaments.Non-limiting examples of polymers that may be spun into filamentsinclude natural polymers, such as starch, starch derivatives, cellulose,such as rayon and/or lyocell, and cellulose derivatives, hemicellulose,hemicellulose derivatives, and synthetic polymers including, but notlimited topolyvinyl alcohol filaments and/or polyvinyl alcoholderivative filaments, and thermoplastic polymers such as polyesters,nylons, polyolefins such as polypropylene, polyethylene, and copolymersthereof, and biodegradable or compostable thermoplastics such aspolylactic acid, polyhydroxyalkanoate, polyesteramide, andpolycaprolactone; bio-sourced or bi-derived polymers (such as but notlimited to bio-sourced polyethylene); and recycled polymeric materials(such as but not limited to recycled PET). Spun filaments may bemonocomponent or multicomponent, for example, bicomponent.

The “region basis weight” of a region of a section of formed nonwovenweb material means the weight in grams of the region of interest,divided by its surface area on one side, measured by any appropriatemeasurement technique including but not necessarily limited to theLocalized Basis Weight measurement method described herein.

“Intensive properties” of a region of a nonwoven web material includebasis weight; aggregate total of the lengths of all fibers and/orfilaments present per unit surface area of the material lying along anx-y plane (referred to herein as fiber and/or filament “area density”);caliper/thickness in the z-direction; and density (mass per unitvolume).

“Lateral,” with respect to a feminine hygiene pad, adult incontinencepad, or disposable diaper, refers to the direction perpendicular to thelongitudinal direction, and from side-to-side of the article from thewearer's perspective.

“Longitudinal,” with respect to a feminine hygiene pad, adultincontinence pad, or disposable diaper, refers to the direction fromfront-to-rear or from rear-to-front of the article from the wearer'sperspective.

“Nonwoven,” with respect to a fabric of web of material, means a fabricor web formed predominately of fibers, filaments or a combinationthereof, which are not knitted or woven, but rather are laid down andaccumulated into a batt and then consolidated and held together in acoherent fabric web of material by entangling, a dispersed bindingagent, a pattern of discrete bonds formed by localized deposits ofadhesive, localized thermal fusing, localized plastic deformation andentanglement between fibers or filaments caused by localizedapplications of pressure, or a combination thereof.

“Ordered arrangement,” with respect to a section of formed nonwoven webmaterial having a regular (repeating) pattern or configuration of zonesthat each include adjacent regions of differing intensive properties, oran irregular (non-repeating) pattern or configuration of zones that eachinclude adjacent regions of differing intensive properties, along asurface of the material, means an arrangement of such zones that isrecognizable by a person of ordinary skill in the art of nonwoven webmanufacturing as an ordered, non-random arrangement or pattern, ascontrasted with a random, unordered accumulation and distribution offilaments and/or fibers. As will be recognized by persons of ordinaryskill in the art relevant to this disclosure, an ordered arrangement ofsuch zones will result from process steps and equipment used tomanufacture the nonwoven web material, configured to repeatably effectthe ordered arrangement in the nonwoven web material. An orderedarrangement of zones in a nonwoven web material may reflect an orderedarrangement of features of forming equipment, such as an orderedarrangement of features on a forming belt.

“Visually discernible” means visible and visually detectable from adistance of approximately 0.5 meter or more, to the naked eye of anordinary observer having 20/20 vision, under indoor office lightingconditions deemed appropriate for reading printed text media.

A “zone” is a zone of a nonwoven web material comprising at least firstand second adjacent regions thereof, the first and second adjacentregions having differences in one or a combination of basis weight,caliper, density (mass/volume), and/or fiber and/or filament areadensity.

A “region” is a sub-portion of a “zone”, defined by and distinguishedfrom other sub-portions of the zone by one or a combination of adifference in basis weight, caliper, density (mass/volume), and/or fiberand/or filament area density.

An ordered arrangement of “attenuated regions” of relatively low basisweight in a nonwoven material, wherein filaments are present inrelatively low numbers, is distinguishable from an ordered arrangementof apertures or holes through a nonwoven material, in that “attenuatedregions” in an ordered arrangement have randomly and varyingly locatedand varyingly oriented filaments passing thereacross between portions ofan adjacent built-up region(s) of relatively higher basis weight,whereas apertures or holes in an ordered arrangement will have anidentifiable, consistent absence of filaments passing thereacrossbetween neighboring unapertured portions.

A “discrete” low bulk portion or “discrete” attenuated region means onethat is entirely surrounded (in an x-y plane) by a continuous area ofbuilt-up region, and has a largest dimension in the x-y plane no greaterthan 1 cm.

“z-direction,” with respect to a nonwoven web material or portionthereof lying along an x-y plane, means the direction orthogonal to thex-y plane. “z-direction,” with respect to a forming belt used tomanufacture a nonwoven web material moving through a working location ofbelt travel lying along an x-y plane, means the direction orthogonal tothe x-y plane.

“Liquid-permeable” and “liquid-impermeable” refer to the penetrabilityof materials in the context of the intended usage of disposableabsorbent articles. Specifically, the term “liquid-permeable” refers toa layer or a layered structure having pores, openings, and/orinterconnected void spaces that permit aqueous liquid such as water,urine, or synthetic urine to pass through its thickness in the absenceof a forcing pressure. Conversely, the term “liquid-impermeable” refersto a layer or a layered structure through the thickness of which aqueousliquid such as water, urine, or synthetic urine cannot pass in theabsence of a forcing pressure (aside from natural forces such asgravity). A layer or a layered structure that is liquid-impermeableaccording to this definition may be permeable to liquid vapor, i.e., maybe “vapor-permeable.”

With respect to a component of a wearable absorbent article constructedof a plurality of components, a “wearer-facing” component is thecomponent disposed closest to the wearer's skin when the article isworn, and an “outward-facing” component is the component disposedfurthest from the wearer's skin. With respect to two opposing majorsurfaces of a web, sheet or batt component of a wearable absorbentarticle, the “wearer-facing” surface is the surface facing the wearer'sskin when the article is worn, and the opposing “outward-facing” surfaceis the surface facing away from the wearer's skin.

Absorbent Articles

Referring to FIGS. 1-4, a wearable absorbent article may have the formof a feminine hygiene pad 110. Pad 110 has a longitudinal axis 111 and alateral axis 112 and may include a wearer-facing, liquid-permeabletopsheet 120, outward-facing, liquid-impermeable backsheet 130, and anabsorbent structure 140 disposed between and enveloped by the topsheetand backsheet. It will be recognized that adult incontinence pads,disposable absorbent pants and disposable diapers also may include thisgeneral structure.

Many currently marketed feminine hygiene pads 110 include wing portionssuch as depicted wing portions 114. Some currently marketed adultincontinence pads also include wing portions of similar positioning andconfiguration. Wing portions 114 may be portions of one or both of thetopsheet and backsheet materials, without any substantial portion of theabsorbent structure 140 or quantity of absorbent material between them,which extend laterally away from the longitudinal axis 111. Referring toFIGS. 3 and 4, wing portions 114 may be provided to allow the user toplace the pad 110 inside the user's underpants over the crotch portion300 thereof, and fold and wrap the wing portions 114 over the insides ofthe respective left and right leg opening edges 301 a, 301 b of theunderpants, through the leg openings and about the outer surface of theunderpants in the crotch region. Wing portions 114 may be provided withdeposited patches of adhesive 116 to allow the user to adhere the wingportions 114 to the outer surface of the underpants in the crotchportion 300, helping hold the pad in place within the underpants duringwear, and protecting the underpants about the leg opening edges fromstaining by exudates. When included and used for these purposes, wingportions 114 are required to flex and/or fold along approximatelylongitudinal wing fold lines 115 (see FIGS. 1 and 4). For purposesherein, a wing portion 114 of a feminine hygiene pad 110 may beidentified as a portion that includes no substantial portion of theabsorbent structure 140 and no substantial quantity of absorbentmaterial therewithin, the portion having a profile that extendslaterally away from the longitudinal axis 111 of the pad, beginningapproximately at a forward inflection point 114 b where the outerperimeter changes direction, away from a direction approximatelyparallel the longitudinal axis toward a direction perpendicular to thelongitudinal axis, and ending approximately at a rearward inflectionpoint 114 c where the outer perimeter approaches the longitudinal axisand then changes direction away from a direction perpendicular thelongitudinal axis, toward a direction to parallel to the longitudinalaxis, where inflection points 114 b, 114 c are the two points along theperimeter that are closer to the longitudinal axis than any other pointsalong the perimeter of the wing portion. See, e.g., FIG. 1. The wingportion may be substantially delineated from the main portion of the padby a line connecting the two inflection points 114 b, 114 c.

When wing portions 114 of a pad 110 are folded for use as describedabove, the topsheet has an in-use wearer-facing surface 126 that doesnot include the wing portions 114. In-use wearer-facing surface 126 hasan outer perimeter 128. In other types of pads and diapers, wingportions 114 may be omitted, in which circumstance the in-usewearer-facing surface 126 of the topsheet and the outer perimeter 128may be coextensive. Various non-limiting examples of possible topsheetswith in-use wearer-facing portions 126 and outer perimeters 128 thereofare illustrated in FIGS. 5A-5D. As suggested in FIGS. 5A, 5B and 5D,wing portions 114 with outer edges 114 a may be included, or may beomitted, depending upon the style of article desired to be provided. Assuggested in FIG. 5C, some types of wearable absorbent articles such asdisposable diapers may have topsheets 120 with a simple rectangularshape.

Formed Topsheet Features

Referring now to FIGS. 6-10, a topsheet 120 for an absorbent articlesuch as a feminine hygiene pad may be formed of a section of formednonwoven web material imparted with certain features to enhance visualappearance and provide beneficial functionality. A topsheet 120 formedof a section of formed nonwoven web material may be provided with one ormore attenuated regions 163 defining channel portions 164. Channelportions 164 may be disposed to the inside of, proximate to, and mayapproximately parallel, outer perimeter 128 of in-use wearer-facingportion. Although depicted as defining continuous oval- orstadium-shapes in FIG. 6, channel portions 164 may be discontinuous, andmay be present only along the sides, only along the ends, or portions orintervals, of in-use wearer-facing portion 126 of topsheet 120 withouter perimeter 128.

For purposes of reducing the chances of exudate fluid migration acrossthe topsheet to the edges thereof, it may be desired that theconfiguration of channel portion(s) 164 have certain features.

In some examples, it may be desired than any configuration of channelportion(s) 164 that is present, not have a portion that extendscontinuously along a path from an area proximate a discharge locus outto any edge of the topsheet. Avoiding inclusion of such a channelportion will avoid creating a channel for discharged fluid to migrate toan edge of the topsheet or in-use wearer-facing portion 126 thereof,with the attendant possibility of leakage of discharged fluid off thepad.

In non-limiting examples such as depicted in FIGS. 22 and 23A-23K, itmay be desired that a configuration of channel portion(s) 164 besubstantially symmetric about longitudinal axis 111 of the topsheet 120and/or of the article 110.

In some examples such as some types and/or sizes of feminine hygienepads and baby diapers, it may be desired that a configuration of channelportion(s) 164 be longitudinally centered about a lateral dischargelocus 112 b that is offset from the lateral axis 112 of the article (asidentified in FIG. 1), such that the configuration of channel portion(s)164 is not longitudinally centered or symmetric about lateral axis 112.

For a feminine hygiene pad, for example, this configuration may bedesired where it is preferred that the pad be placed within the user'sunderpants such that a greater proportion of absorbent structure surfacearea within the x-y plane be located rearward of the expected dischargelocus 112 b (which is the location on the article expected to firstreceive a discharge of fluid during normal use of the article, locatedalong the longitudinal axis 111 and at the midpoint of the longitudinaldimension of the configuration of channel portion(s) 164). For example,for some types and sizes of feminine hygiene pads, it may be desiredthat the greater proportion of absorbent structure surface area belocated to the rear of the expected discharge locus 112 b on thetopsheet (where the discharge locus 112 b is the location on thetopsheet expected to be most proximate the user's vaginal opening duringuse/wear). In such examples it may be preferred that the greaterproportion of absorbent structure surface area be located rearward ofthe discharge locus because discharged menstrual fluid often movesrearward through a pad as a result of proximity of the pad to the user'sbody as held in place by underpants, anatomical features and typicalranges of body positions and movements during use/wear. When theconfiguration of channel portion(s) 164 is visually discernible whenformed as described herein, its visible location may serve to guide theuser in appropriately locating and placing the pad within the user'sunderpants for use/wear. In some examples, any wing portions 114included may be approximately longitudinally centered about the lateraldischarge locus 112 b, as suggested by way of non-limiting example inFIG. 22.

In other examples, it may be desired that the configuration of channelportion(s) 164 be longitudinally centered about the lateral axis 112 ofthe article, and for some examples, be symmetric about the lateral axis112. In such examples, the expected discharge locus may be at theintersection between the longitudinal axis 111 and lateral axis 112.

In many circumstances, it may be desired that a configuration of one ormore channel portions 164 occupy one or more paths that, individually orin combination, predominately circumscribe a discharge locus 112 b.Referring to FIGS. 24A-24C, for purposes herein, a path or plurality ofpaths of a configuration of channel portions 164 “predominatelycircumscribe” a discharge locus 112 b, when a ray drawn in the x-y planealong the pad surface, originating at a discharge locus 112 b andextending radially outwardly in the x-y plane therefrom, will intersecta channel portion 164 when drawn in any of a predominately greaternumber of possible angular positions about a 360-degree circle with itscenter at the discharge locus 112 b. Referring to FIGS. 24A-24C, by wayof illustration, angles α delineate angular portions of a circle withinwhich any ray extending from the center thereof will intersect a channelportion 164; and angles 13 delineate angular portions of the circlewithin which any ray extending from the center will not intersect achannel portion 164. Thus, each of the illustrative examples of channelportion 164 configurations shown in FIGS. 24A-24C predominatelycircumscribe a discharge locus 112 b, because the total of the angles αis greater than the total of the angles β, i.e., total of angles α isgreater than 180 degrees. For FIGS. 24A and 24B,

(α₁+α₂)>(β₁+β₂);

and for FIG. 24C,

(α₁+α₂+α₃+α₄)>(β₁+β₂+β₃+β₄).

For purposes of identifying a discharge locus 112 b and determiningwhether a configuration of channel portion(s) 164 predominatelycircumscribes it, a discharge locus 112 b may lie anywhere on orapproximately on longitudinal axis 111, at any point therealong that ispredominately circumscribed by a configuration of channel portion(s) 164as described above and is within the middle third of the length of thetopsheet along the longitudinal axis 111. To illustrate, referring toFIG. 24E, a discharge locus 112 b _(A) is predominately circumscribed bychannel portion 164 because angle α_(A) is greater than angle β_(A),where such a discharge locus 112 b _(A) may be identified alonglongitudinal axis 111 within the middle third (⅓Lm) of length L. Thecondition is satisfied in any example in which such a discharge locussuch as locus 112 b _(A) may be identified, despite the possibility,with some configurations of channel portions 164, of identifyingalternate locations such as location 112 b _(B) along axis 111 where,e.g., angle α_(B) is less than angle β_(B).

An example of a configuration of channel portion(s) 164 that does notpredominately circumscribe a discharge locus is illustrated in FIG. 24D.The configuration shown in FIG. 24D does not predominately circumscribea discharge locus because no discharge locus can be identified withinthe middle third (⅓Lm) of length L, where angle α is greater than angleβ. In the example illustrated in FIG. 24D, even when a possibledischarge locus is identified at the very edge of middle third (⅓Lm) oflength L as shown, angle α is less than angle β. (In the exampledepicted in FIG. 24D, angle α is less than 180 degrees.)

From the foregoing description and from the associated figures, it willbe appreciated that absence of a discharge locus within the middle thirdof the length of the pad, that is predominately circumscribed by aconfiguration of channel portion(s) 164, makes it less likely that aconfiguration of channel portion(s) 164 will be positioned to capture,channel, promote absorption of, and thereby help prevent migration ofdischarged fluid outwardly toward an edge of the topsheet.

Other non-limiting examples of configurations of channel portion(s) 164are illustrated in FIGS. 23A-K, which are proportional as shown, and asshown, would predominately circumscribe a discharge locus located withinthe middle third of the length of a pad.

It may be desired that channel portion(s) 164 overlie the absorbentstructure 140 of the article (in the z-direction), and preferably, bepresent only in locations on the topsheet overlying the absorbentstructure. This is to ensure that any fluid channeled by channelportion(s) 164 is channeled along locations on the topsheet that areunderlaid in the z-direction by the absorbent structure, such thatchannel portion(s) 164 are suitably disposed to facilitate absorption bythe underlying absorbent structure 140, through the bottom(s) of thechannel portion(s) 164.

Referring again to FIGS. 8-10, it can be seen that channel portions 164are portions of the section of formed nonwoven web material formingtopsheet 120 in which filaments 122 forming portions of the formednonwoven web material are present in substantially lesser quantity thanin built-up regions 166. The respective channel portions 164 andadjacent built-up regions 166 in a nonwoven web material may be formedby a process described below.

Referring to FIG. 9, any number of zones 160 may be identified. Eachzone includes at least one attenuated region 163 having a relativelysubstantially lesser fiber and/or filament area density adjacent to atleast one built-up region 166 having a relatively substantially greaterfiber and/or filament area density. Corresponding to the relativelylesser fiber and/or filament area density of the attenuated regions 163and relatively greater fiber and/or filament area density of thebuilt-up regions 166, attenuated regions 163 may have a relatively lowerbasis weight than adjacent built-up regions 166. The nonwoven webmaterial may be manufactured as described below, such that thesedifferences between adjacent regions 163, 166 within a zone 160 may bevisually discernible. Visual discernibility of these regions and zonesmay be manifest in visible localized differences/variations in filamentand/or fiber area density, web thickness/caliper and/or webtransparency/opacity. For example, a viewer may perceive channelportions 164 in a section of formed nonwoven web material forming atopsheet 120 to be channels or grooves following oval-shaped paths alongthe surface of the topsheet 120, wherein the channels or grooves arevisually discernible as regions of visually, discernibly lower filamentand/or fiber area density, visually, discernibly lower webthickness/caliper and or visually, discernibly lower web opacity(conversely, higher translucency). In order to substantially ensure orenhance visual discernibility as well as the other functional aspects ofthe topsheet features described herein, it may be desired to control thefilament deposition process and distribution between attenuated regions163 and built-up regions 166, such that they differ in average basisweight by at least a factor of 2. As discussed below, distribution offilaments between attenuated regions and built-up regions may becontrolled by selection of a substrate forming belt material for a givenair permeability, and by control of the airflow drawing rate of theforming vacuum system.

Such channels or grooves may serve esthetic/decorative and functionalpurposes. A user/consumer of a feminine hygiene pad product having suchfeatures may perceive visible channels/grooves (with built-up regionstherebetween and/or surrounding them) to serve a containment function byproviding physical barriers to flow of exudate fluids across the surfaceof the pad and off the side(s) or end(s) thereof. In some configurationsthe combination of such channel portions with built-up regionstherebetween or surrounding them may actually serve such a barrierfunction. The channel portions 164 may literally constitute channels inand along which exudate fluids may more freely collect and flow, whilethe surrounding built-up regions 166 may constitute physical barrierstending to inhibit fluid in the channels from flowing longitudinally orlaterally outward toward the edge (outer perimeter 128) of the pad. Thismay be particularly true when filaments and/or fibers forming the padhave been spun from polymer resins (without or withhydrophobicity-enhancing melt additives) having hydrophobic surfaceenergy properties, which can inhibit flow of aqueous fluids along theirsurfaces.

It will be appreciated that configurations of channel portions 164 suchas those non-limiting examples described above and illustrated in FIGS.6 and 23A-23K may provide visual appeal and liquid containmentfunctionality not only to topsheets for feminine hygiene pads, but alsoto topsheets for adult incontinence pads, disposable absorbent pants anddisposable diapers.

Referring to FIGS. 6-8, a section of formed nonwoven web materialforming topsheet 120 of a feminine hygiene pad or adult incontinence padmay include one or more attenuated regions 163 defining hinge portions168 formed therein, proximate to wing fold lines 115. Hinge portions 168may extend approximately longitudinally along any portion, orsubstantially all, of the longitudinal length of wing portions 114 wherethey extend away from the main (central) portion of the pad. Hingeportions 168 may be formed in a manner similar to the manner in whichchannel portions 164 may be formed, as will be described below. Likechannel portions 164, hinge portions 168 may be adapted to be visuallydiscernible, and may include visually discernible attenuated regions ofcomparatively lesser filament and/or fiber area density and basisweight, adjacent visually discernible built-up regions of comparativelygreater filament and/or fiber area density and basis weight, withinvisually discernible zones. Because they are arranged longitudinallyproximate to line(s) 115 along which wing portions are desirably foldedto wrap about the crotch portion of underpants, and because they mayconstitute areas of visibly reduced presence of filaments and/or fibersand/or visibly reduced topsheet thickness/caliper, hinge portions 168may serve to visually indicate a folding location. Additionally, thereduced number of filaments and/or fibers in hinge portions 168 causesthe web material therealong to be less stiff than the surroundingbuilt-up regions 166, functionally promoting and facilitating foldingalong the hinge portions.

In addition or as an alternative to providing hinge structures forwings, configurations of hinge portions 168 may be located along otherportions of the topsheet to enhance flexibility, comfort and/or bodyconformity. Referring to FIG. 25, by way of non-limiting example, hingeportions 168 may be included to provide lines or paths along which thecorners of the pad are enabled to more easily flex, to allow the pad tobetter and/or more comfortably conform to the user/wearer's body duringwear.

It will be appreciated that a characteristic of a hinge portion 168 maybe that it follows or parallels a path or line that extends between twoedges of the topsheet where it defines wings 114, and one or moreattenuated regions 163 occupy the majority of such path and form thehinge portion 168.

Other Ordered Arrangements

An advantage provided by the forming belt manufacturing techniquedescribed below and in the references incorporated by reference in thepresent disclosure, however, is that airflow blocking structures 262 maybe formed and configured on a forming belt 260 according to an unlimitednumber of variants of desired combinations of recognizable, visuallydiscernible shapes, images of natural or artificial objects, people,animals, fanciful characters, anthropomorphic characters, decorativeelements, functional features, designs, patterns, sizes, spacings etc.,by simply printing the negative of the desired configuration on the maskused to selectively block resin-curing light, as described below. Itwill be appreciated, therefore, that in addition to forming airflowblocking structures to impart the channel portions 164 and hingeportions 168 to a nonwoven web material formed on a forming belt asdescribed herein, the airflow blocking structures may be designed andincluded on a forming belt to impart other functional features,decorative/ornamental features, or a combination thereof, to thenonwoven web material. FIGS. 18 and 19 illustrate two possible,non-limiting examples. In the examples shown in FIGS. 18 and 19, apattern 275 of continuous low bulk portions 164 a formed of attenuatedregion(s) 163, and defining a pattern of diamond-shaped built-up regions166, may be formed on a section of formed nonwoven web material to forma feminine hygiene pad topsheet, in combination with one or more channelportions 164 and/or hinge portions 168. It will be appreciated that apattern such as pattern 275 may be desired for functional and/ordecorative purposes. In the examples depicted in FIGS. 18 and 19,pattern 275 of low bulk portions 164 a may serve both purposes, byimparting a visually pleasing decorative appearance to the topsheet, andby providing a network of channel-like structures that may function asfluid channels in a manner similar to the channel portions 164 asdescribed above, serving to help distribute flows of body exudate fluidacross the pad surface area and drain them to underlying absorbentstructure, while built-up regions 166 may serve to maintain separationbetween the channel-like structures' lower z-direction depths (andexudate fluid they carry) from the wearer's skin. Pattern 275 of lowbulk portions 164 a may be imparted by use of a forming belt with asuitable corresponding pattern of airflow blocking structures formedthereon, in the manner described below. As suggested by FIGS. 18 and 19,it may be desired in some circumstances that any pattern 275configuration of continuous low bulk portions does not include portionsthat extend beyond the edges of the absorbent structure, oralternatively, to the edges of the topsheet, so as to avoid channelingexudate fluids to positions at which they may be unlikely to be absorbedby the absorbent structure, and/or might flow off the edges of the pad.

An unlimited number of other patterns 275 of attenuated regions andbuilt-up regions are possible. As reflected in the additionalnon-limiting examples of FIGS. 26A, 26B and 27, it may be desired insome circumstances for a topsheet in its longitudinally and laterallycentral areas to include a pattern 275 of discrete low bulk portions 165which, rather than being continuous across a substantial portion of thelength or width of the topsheet in the manner of channel portions, andrather than intersecting or interconnecting with other low bulk portions164 a as suggested in FIGS. 18 and 19, are each discrete and entirelysurrounded by a continuous area of built-up region 166, like “islands”(corresponding with low bulk portions 165) in a “sea” (correspondingwith built-up region 166). A pattern of such discrete low bulk portions165, without any traversing channel portions, may be included and mayoccupy a central area of the topsheet proximate a discharge locus and/orat the intersection of the longitudinal and lateral axes 111, 112.Non-limiting examples of such patterns are depicted in FIGS. 26A and26B, appearing in the laterally central portions of the images andextending from top to bottom. In such examples each discrete low bulkportion 165, being relatively sparsely populated by filaments, canbetter serve as a pathway for fluid to move in a z-direction through thetopsheet (behaving in a manner akin to a drain hole through thetopsheet), while the surrounding, continuous built-up region 166 canserve as a barrier to inhibit x-y-direction lateral/longitudinal flowand thereby inhibit spreading of discharged fluid across the topsheet.These effects may be enhanced by manipulation of thehydrophobic/hydrophilic characteristics of various surfaces, portionsand/or regions of the web from which the topsheet is made, through thetechniques, materials and configurations described below. It has beenlearned that, generally, consumers/users of feminine hygiene pads preferpads configured such that discharged menstrual fluid effectively movessuitably rapidly through the topsheet in a z-direction to absorbentmaterial beneath, such that the x-y dimensions of staining of thetopsheet by received fluid are as small as possible and centralizedabout the discharge locus. This visual signal indicates to the user thatthe absorbent system is working effectively to receive, capture andcontain discharged fluid. Thus, a pattern of low bulk portions 164 asuch as depicted by way of non-limiting examples in FIGS. 26A and 26B,that does not include continuous channels such as depicted in FIGS. 18and 19 at the intersection of the lateral and longitudinal axes and/orproximate the expected discharge locus 112 b on the topsheet, may bepreferred. Without intending to be bound by theory, it is believed thata pattern of discrete low bulk portions 165 occupying a total area (suchas an area that is predominately circumscribed by one or more channelportions 164), is most effective at draining fluid in a z-direction whenthe discrete low bulk portions 165 occupy a fraction of the total areaoccupied by the pattern of 5 percent to 30 percent, more preferably 8percent to 25 percent, and even more preferably 10 percent to 22percent, of the total area occupied by the pattern.

For purposes herein, the percent fraction of the total area occupied bydiscrete low bulk portions reflects, and may be determined by,measurement of the corresponding area of the airflow blocked regions 264in the x-y plane on the forming belt 260 used to form the topsheetmaterial (described below), which, in turn, may also be reflected bycorresponding resin curing regions 264 a and/or resin non-curing regions263 a on a mask used to make the forming belt (according to themanufacturing method described below). Additionally, the percentfraction of a total area occupied by a pattern of discrete low bulkportions 165 may be measured directly from the topsheet web itself usinga Pattern Analysis Test as described in either of U.S. ProvisionalApplications Ser. Nos. 62/842,792 and 62/842,807. Where a range forpercent fraction of a total area occupied by a pattern of discrete lowbulk portions 165 is specified and/or recited in a claim herein, it isintended to apply to and cover such range as may be determined by any ofthe methods identified in this paragraph. If a Pattern Analysis Test setforth in one of the applications referenced above is found to beinsufficient to measure such percent fraction under particularcircumstances, resort to one of the other methods (e.g. measurement ofarea of airflow blocked regions 264 on forming belt, or measurement ofarea of resin curing regions 264 a and/or resin non-curing regions 263 aon a mask) may be had.

By way of particular, non-limiting example, referring to FIG. 22, if thetotal area circumscribed by channel portion 164 is occupied by a patternof discrete low bulk portions collectively occupying 8 percent to 22percent of the area occupied by the pattern, it is believed that optimalz-direction fluid draining effect may be achieved for the topsheetconfiguration.

In addition to controlling the area collectively occupied by discretelow bulk portions in a pattern thereof, their individual sizes may beregulated (via design of the forming belt 260, as described below) forbeneficial effect. If a majority or all of the discrete low bulkportions 165 in the pattern each have an area of at least 0.8 mm² and nogreater than 20 mm², more preferably no greater than 7 mm², userperceptions of tactile softness of the topsheet may be enhanced, whilechances of exposure of the user's skin to the wet absorbent structurewill be minimized while still maintaining optimal draining performanceand control of stain spreading. (When the discrete low bulk portionshave a circular shape, the ranges set forth immediately above equatewith a low bulk portion diameter of at least 1 mm and no greater than 5mm, more preferably no greater than 3 mm.)

As suggested in FIGS. 26A, 26B and 27, a pattern 275 of discrete lowbulk portions 165 occupying longitudinally and/or laterally centralportions of the topsheet of may be partially or entirely surrounded byone or more channel portions 164. One or more channel portions 164 maybe configured to predominately circumscribe a discharge locus 112 b andotherwise function as described above. A pattern of low bulk portionspresent proximate and/or about the intersection of the lateral andlongitudinal axes and/or at the expected discharge locus 112 b on thetopsheet may be included within any of the configurations of channelportions 164 described herein, and illustrated by way of non-limitingexample in FIGS. 6, 22, 23A-23K, 24A, 24B, 24C, 24E and 25.

As will be apparent from the description below, the method and processof formation of the web material will result in “sidedness,” wherein onex-y surface of the formed web material exhibits a substantially greatervisible topography with visible z-direction “heights” of well-definedbuilt-up regions (on the side most proximate the forming belt duringformation—forming belt side), than does the opposing x-y surface(opposite side). This sidedness makes it desirable that, when the webmaterial is used to form a topsheet, the forming belt side faces thewearer on the end product. This makes the topography more visible to thewearer, may enhance visual and tactile softness signals conveyed by thetopographical features, and facilitates the functionality of thetopsheet as described herein.

Absorbent Structure

The absorbent structure 140 as contemplated herein may have any suitablex-y plane perimeter shape including but not limited to an oval shape, astadium shape, a rectangle shape, an asymmetric shape, and an hourglassshape. In some examples, the absorbent structure 140 may be impartedwith a contoured shape, e.g. narrower in an intermediate region than inthe forward and rearward end regions. In other examples, the absorbentstructure may have a tapered shape having a wider portion in one endregion of the pad which tapers to a narrower end region in the other endregion of the pad. The absorbent structure 140 may stiffness that variesalong one or both the longitudinal and lateral directions.

The absorbent structure 140 may have one or more layers. In certainembodiments, there are two absorbent layers where there is a firstabsorbent layer and a second absorbent layer adjacent to the firstabsorbent layer. These materials are preferably compressible,conformable, non-irritating to the wearer's skin, and capable ofabsorbing and retaining liquids such as urine and other certain bodyexudates including menses.

The first absorbent layer may include a first layer of absorbentmaterial, which may be 100% or less of particles of superabsorbentpolymer (SAP) (also known as absorbent gelling material or AGM), such as85% to 100% SAP, 90% to 100% SAP, or even 95% to 100% SAP, specificallyincluding all 0.5% increments within the specified ranges and all rangesformed therein or thereby. The second absorbent layer may include asecond layer of absorbent material, which may also be 100% or less ofSAP (including the ranges specified above). Alternatively, either orboth the first and second absorbent layer may include a combination ofcellulose, commuted wood pulp, or the like, in combination with SAP. Insome examples, the absorbent structure may include a first layer and asecond layer, wherein the first layer is designed primarily forabsorbing and retaining fluid (sometimes known as a storage layer). Thestorage layer may include particles of SAP and may include particles ofSAP distributed within a batt of cellulosic fiber. The second layer(sometimes known as an acquisition/distribution layer or “secondarytopsheet”) may be designed to be disposed directly beneath the topsheetand configured for receiving and dispersing energy from a gush of fluid,and distributing the fluid across and down to the storage layer. Theacquisition/distribution layer may be a batt or nonwoven structure offilaments or fibers which may be partially or entirely cellulosicfibers, or a blend of cellulosic fibers and polymeric fibers orfilaments. In particular examples the acquisition/distribution layer maybe an airlaid batt of cellulosic fibers.

Alternatively, the absorbent structure may be formed entirely/solely ofcellulosic fiber (including cellulosic fiber material known as“airfelt”) as the absorbent material.

The absorbent structure 140 may also comprise a carrier layer for eitheror both of first and second absorbent layers. This carrier layer may bea nonwoven web, which may be apertured. The absorbent structure 140 mayalso include a thermoplastic adhesive material at least partiallybonding a layer of the absorbent material to a substrate material.

The absorbent structure 140 may include one or more grooves, channels orpockets that are defined by z-direction depressions or changes incaliper of layer(s) of the absorbent structure. The one or more grooves,channels or pockets may be provided in addition to one or more channelsor instead of the one or more channels in the topsheet. The pockets maybe areas in the absorbent structure that are free of, or substantiallyfree of absorbent material, such as SAP (including the ranges specifiedabove). Other forms and more details regarding channels and pockets thatare free of, or substantially free of absorbent materials, such as SAP,within absorbent structures are discussed in greater detail in US2014/0163500; US 2014/0163506; and US 2014/0163511.

The configuration and construction of the absorbent structure 140 mayvary (e.g., the absorbent structure 140 may have varying caliper zones,a hydrophilic gradient, a superabsorbent gradient, or lower averagedensity and lower average basis weight acquisition zones). Further, thesize and absorbent capacity of the absorbent structure 140 may also bevaried to accommodate a variety of wearers. However, the total absorbentcapacity of the absorbent structure 140 should be compatible with thedesign loading and the intended use of the sanitary napkin or any otherdisposable absorbent article.

In some forms contemplated herein, the absorbent structure 140 maycomprise a plurality of multi-functional layers in addition to the firstand second absorbent layers. For example, the absorbent structure 140may comprise a core wrap (not shown) useful for enveloping the first andsecond absorbent layers and other optional layers. The core wrap may beformed by two nonwoven materials, substrates, laminates, films, or othermaterials. The core wrap may only comprise a single material, substrate,laminate, or other material wrapped at least partially around itself.

The absorbent structure 140 may comprise one or more adhesives, forexample, to help immobilize any superabsorbent gelling material or otherabsorbent materials that might be present in the core.

Absorbent structures comprising relatively high amounts of SAP withvarious core designs are disclosed in U.S. Pat. No. 5,599,335; EP 1 447066; WO 95/11652; US 2008/0312622A1; and WO 2012/052172. These designsmay be used to configure the first and second superabsorbent layers.Alternate core embodiments are also described in U.S. Pat. Nos.4,610,678; 4,673,402; 4,888,231; and 4,834,735. The absorbent structuremay further comprise additional layers that mimic a dual core systemcontaining an acquisition/distribution core of chemically stiffenedfibers positioned over an absorbent storage core as described in U.S.Pat. No. 5,234,423 and in U.S. Pat. No. 5,147,345.

Superabsorbent polymers as contemplated herein are typically used in theform of discrete particles. Such superabsorbent polymer particles can beof any desired shape, e.g., spherical or semi-spherical, cubic, rod-likepolyhedral, etc. Shapes having a large greatest dimension/smallestdimension ratio, like needles and flakes, are also contemplated for useherein. Agglomerates of fluid absorbent gelling material particles mayalso be used.

The size of the fluid absorbent gelling material particles may vary overa wide range. For reasons of industrial hygiene, average particle sizessmaller than about 30 microns are less desirable. Particles having asmallest dimension larger than about 2 mm may also cause a feeling ofgrittiness in the absorbent article, which is undesirable from aconsumer aesthetics standpoint. Furthermore, rate of fluid absorptioncan be affected by particle size. Larger particles have very muchreduced rates of absorption. Fluid absorbent gelling material particlespreferably have a particle size of about 30 microns to about 2 mm forsubstantially all of the particles. “Particle Size” as used herein meansthe weighted average of the smallest dimension of the individualparticles.

These layers are preferably substantially free of airfelt and are thusdistinct from mixed layers that may include airfelt. As used herein,“substantially free of airfelt” means less than 5%, 3%, 1%, or even 0.5%of airfelt. In a preferred case, there will be no measurable airfelt inthe superabsorbent layers of the absorbent structure. In the case of thefirst superabsorbent layer, it is preferably disposed onto the firstdistribution layer discontinuously. As used herein “discontinuously” or“in a discontinuous pattern” means that the superabsorbent polymers areapplied onto the first distribution layer in a pattern of disconnectedshaped areas. These areas of superabsorbent polymers or areas free ofsuperabsorbent polymer may include, but are not limited to linearstrips, non-linear strips, circles, rectangles, triangles, waves, mesh,and combinations thereof. The first superabsorbent layer like the secondsuperabsorbent layer may, however, be disposed onto its respectivedistribution layer in a continuous pattern. As used herein “continuouspattern” or “continuously” means that the material is deposited and orsecured to a superabsorbent carrier material and/or the adjacentdistribution layer in an uninterrupted manner such that there is ratherfull coverage of the distribution layer by the superabsorbent polymer.

In some examples the absorbent structure 140 may be formed of or includea layer of absorbent open-celled foam material. In some examples, thefoam material may include at least first and second sublayers ofabsorbent open-celled foam material, the sublayers being in directface-to-face contact with each other. In such examples, thewearer-facing sublayer may be a relatively larger-celled foam material,and the outward-facing sublayer may be a relatively smaller-celled foammaterial, for purposes explained in more detail below.

The open-celled foam material may be a foam material that ismanufactured via polymerization of the continuous oil phase of awater-in-oil high internal phase emulsion (“HIPE”).

A water-in-oil HIPE has two phases. One phase is a continuous oil phasecomprising monomers to be polymerized, and an emulsifier to helpstabilize the HIPE. The oil phase may also include one or morephotoinitiators. The monomer component may be included in an amount ofabout 80% to about 99%, and in certain examples from about 85% to about95% by weight of the oil phase. The emulsifier component, which issoluble in the oil phase and suitable for forming a stable water-in-oilemulsion may be included in the oil phase in an amount of about 1% toabout 20% by weight of the oil phase. The emulsion may be formed at anemulsification temperature of about 20° C. to about 130° C. and incertain examples from about 50° C. to about 100° C.

In general, the monomers will may be included in an amount of about 20%to about 97% by weight of the oil phase and may include at least onesubstantially water-insoluble monofunctional alkyl acrylate or alkylmethacrylate. For example, monomers of this type may include C4-C18alkyl acrylates and C2-C18 methacrylates, such as ethylhexyl acrylate,butyl acrylate, hexyl acrylate, octyl acrylate, nonyl acrylate, decylacrylate, isodecyl acrylate, tetradecyl acrylate, benzyl acrylate, nonylphenyl acrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, octylmethacrylate, nonyl methacrylate, decyl methacrylate, isodecylmethacrylate, dodecyl methacrylate, tetradecyl methacrylate, andoctadecyl methacrylate.

The oil phase may also include from about 2% to about 40%, and incertain examples from about 10% to about 30%, by weight of the oilphase, a substantially water-insoluble, polyfunctional crosslinkingalkyl acrylate or methacrylate. This crosslinking comonomer, orcrosslinker, is added to confer strength and resilience to the resultingHIPE foam. Examples of crosslinking monomers of this type comprisemonomers containing two or more activated acrylate, methacrylate groups,or combinations thereof. Non-limiting examples of this group include1,6-hexanedioldiacrylate, 1,4-butanedioldimethacrylate,trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, 1,12-dodecyldimethacrylate, 1,14-tetradecanedioldimethacrylate, ethyleneglycol dimethacrylate, neopentyl glycol diacrylate(2,2-dimethylpropanediol diacrylate), hexanediol acrylate methacrylate,glucose pentaacrylate, sorbitan pentaacrylate, and the like. Otherexamples of crosslinkers contain a mixture of acrylate and methacrylatemoieties, such as ethylene glycol acrylate-methacrylate and neopentylglycol acrylate-methacrylate. The ratio of methacrylate:acrylate groupin the mixed crosslinker may be varied from 50:50 to any other ratio asneeded.

Any third substantially water-insoluble comonomer may be added to theoil phase in weight percentages of about 0% to about 15% by weight ofthe oil phase, in certain examples from about 2% to about 8%, to modifyproperties of the HIPE foams. In certain cases, “toughening” monomersmay be desired to impart toughness to the resulting HIPE foam. Theseinclude monomers such as styrene, vinyl chloride, vinylidene chloride,isoprene, and chloroprene. Without being bound by theory, it is believedthat such monomers aid in stabilizing the HIPE during polymerization(also known as “curing”) to provide a more homogeneous and better-formedHIPE foam which results in greater toughness, tensile strength, abrasionresistance, and the like. Monomers may also be added to confer flameretardancy, as disclosed, for example, in U.S. Pat. No. 6,160,028.Monomers may be added to impart color (for example vinyl ferrocene); toimpart fluorescent properties; to impart radiation resistance; to impartopacity to radiation (for example lead tetraacrylate); to dispersecharge; to reflect incident infrared light; to absorb radio waves; tomake surfaces of the HIPE foam struts or cell walls wettable; or for anyother desired property in a HIPE foam. In some cases, these additionalmonomers may slow the overall process of conversion of HIPE to HIPEfoam, the tradeoff being necessary if the desired property is to beconferred. Thus, such monomers can also be used to slow down thepolymerization rate of a HIPE. Examples of monomers of this typecomprise styrene and vinyl chloride.

The oil phase may further include an emulsifier to stabilize the HIPE.Emulsifiers used in a HIPE can include: (a) sorbitan monoesters ofbranched C16-C24 fatty acids; linear unsaturated C16-C22 fatty acids;and linear saturated C12-C14 fatty acids, such as sorbitan monooleate,sorbitan monomyristate, and sorbitan monoesters, sorbitan monolauratediglycerol monooleate (DGMO), polyglycerol monoisostearate (PGMIS), andpolyglycerol monomyristate (PGMM); (b) polyglycerol monoesters of-branched C16-C24 fatty acids, linear unsaturated C16-C22 fatty acids,or linear saturated C12-C14 fatty acids, such as diglycerol monooleate(for example diglycerol monoesters of C18:1 fatty acids), diglycerolmonomyristate, diglycerol monoisostearate, and diglycerol monoesters;(c) diglycerol monoaliphatic ethers of -branched C16-C24 alcohols,linear unsaturated C16-C22 alcohols, and linear saturated C12-C14alcohols, and mixtures of these emulsifiers. See U.S. Pat. Nos.5,287,207 and 5,500,451. Another emulsifier that may be used ispolyglycerol succinate (PGS), which is formed from an alkyl succinate,glycerol, and triglycerol.

Such emulsifiers, and combinations thereof, may be added to the oilphase so that they constitute about 1% to about 20%, in certain examplesabout 2% to about 15%, and in certain other examples about 3% to about12%, of the weight of the oil phase. In certain examples, coemulsifiersmay also be used to provide additional control of cell size, cell sizedistribution, and emulsion stability, particularly at highertemperatures, for example greater than about 65° C. Examples ofcoemulsifiers include phosphatidyl cholines and phosphatidylcholine-containing compositions, aliphatic betaines, long chain C12-C22dialiphatic quaternary ammonium salts, short chain C1-C4 dialiphaticquaternary ammonium salts, long chain C12-C22dialkoyl(alkenoyl)-2-hydroxyethyl, short chain C1-C4 dialiphaticquaternary ammonium salts, long chain C12-C22 dialiphatic imidazoliniumquaternary ammonium salts, short chain C1-C4 dialiphatic imidazoliniumquaternary ammonium salts, long chain C12-C22 monoaliphatic benzylquaternary ammonium salts, long chain C12-C22dialkoyl(alkenoyl)-2-aminoethyl, short chain C1-C4 monoaliphatic benzylquaternary ammonium salts, short chain C1-C4 monohydroxyaliphaticquaternary ammonium salts. In certain examples, ditallow dimethylammonium methyl sulfate (DTDMAMS) may be used as a coemulsifier.

Any photoinitiators included may be included at between about 0.05% andabout 10%, and in some examples between about 0.2% and about 10% byweight of the oil phase. Lower amounts of photoinitiator allow light tobetter penetrate the HIPE foam, which can provide for polymerizationdeeper into the HIPE foam. However, if polymerization is performed in anoxygen-containing environment, it may be desired that there be enoughphotoinitiator present to initiate the polymerization and overcomeoxygen inhibition. Photoinitiators can respond rapidly and efficientlyto a light source with the production of radicals, cations, and otherspecies that are capable of initiating a polymerization reaction.Photoinitiators selected for use in forming foams within contemplationof the present disclosure may absorb UV light at wavelengths of about200 nanometers (nm) to about 800 nm, in certain examples about 250 nm toabout 450 nm. If the photoinitiator is in the oil phase, suitable typesof oil-soluble photoinitiators include benzyl ketals, α-hydroxyalkylphenones, α-amino alkyl phenones, and acylphospine oxides. Examples ofphotoinitiators include 2,4,6-[trimethylbenzoyldiphosphine]oxide incombination with 2-hydroxy-2-methyl-1-phenylpropan-1-one (50:50 blend ofthe two is sold by Ciba Speciality Chemicals, Ludwigshafen, Germany asDAROCUR 4265); benzyl dimethyl ketal (sold by Ciba Geigy as IRGACURE651); α-,α-dimethoxy-α-hydroxy acetophenone (sold by Ciba SpecialityChemicals as DAROCUR 1173); 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one (sold by Ciba SpecialityChemicals as IRGACURE 907); 1-hydroxycyclohexyl-phenyl ketone (sold byCiba Speciality Chemicals as IRGACURE 184);bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide (sold by CibaSpeciality Chemicals as IRGACURE 819); diethoxyacetophenone, and4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-methylpropyl)ketone (sold by CibaSpeciality Chemicals as IRGACURE 2959); and Oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone] (sold byLamberti spa, Gallarate, Italy as ESACURE KIP EM.

The dispersed aqueous phase of a HIPE comprises water, and may alsocomprise one or more components, such as initiator, photoinitiator, orelectrolyte, wherein in certain examples, the one or more components areat least partially water soluble.

One component included in the aqueous phase may be a water-solubleelectrolyte. The water phase may contain from about 0.2% to about 40%,in certain examples from about 2% to about 20%, by weight of the aqueousphase of a water-soluble electrolyte. The electrolyte minimizes thetendency of monomers, comonomers, and crosslinkers that are primarilyoil soluble to also dissolve in the aqueous phase. Examples ofelectrolytes include chlorides or sulfates of alkaline earth metals suchas calcium or magnesium and chlorides or sulfates of alkali earth metalssuch as sodium. Such electrolyte can include a buffering agent for thecontrol of pH during the polymerization, including such inorganiccounterions as phosphate, borate, and carbonate, and mixtures thereof.Water soluble monomers may also be used in the aqueous phase, examplesbeing acrylic acid and vinyl acetate.

Another component that may be included in the aqueous phase is awater-soluble free-radical initiator. The initiator can be present at upto about 20 mole percent based on the total moles of polymerizablemonomers present in the oil phase. In certain examples, the initiatormay be included in an amount of about 0.001 to about 10 mole percentbased on the total moles of polymerizable monomers in the oil phase.Suitable initiators include ammonium persulfate, sodium persulfate,potassium persulfate,2,2′-azobis(N,N′-dimethyleneisobutyramidine)dihydrochloride, azoinitiators, redox couples like persulfate-bisulfate, persulfate-ascorbicacid, and other suitable redox initiators. In certain examples, toreduce the potential for premature polymerization which may clog theemulsification system, addition of the initiator to the monomer phasemay be performed near the end of the emulsification step, or shortlyafterward.

Photoinitiator, if included in the aqueous phase, may be at leastpartially water soluble, and may constitute between about 0.05% andabout 10%, and in certain examples between about 0.2% and about 10%, byweight of the oil phase. Lower amounts of photoinitiator allow light tobetter penetrate the HIPE foam, which can provide for polymerizationdeeper into the HIPE foam. However, if polymerization is done in anoxygen-containing environment, there should be enough photoinitiator toinitiate the polymerization and overcome oxygen inhibition.Photoinitiators can respond rapidly and efficiently to a light sourcewith the production of radicals, cations, and other species that arecapable of initiating a polymerization reaction. Photoinitiatorsselected for use to form foams within contemplation of the presentdisclosure may absorb UV light at wavelengths of about 200 nanometers(nm) to about 800 nm, in certain examples from about 200 nm to about 350nm, and in certain examples from about 350 nm to about 450 nm. If aphotoinitiator is to be included in the aqueous phase, suitable types ofwater-soluble photoinitiators may include benzophenones, benzils, andthioxanthones. Examples of photoinitiators include2,2′-Azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride;2,2′-Azobis[2-(2-imidazolin-2-yl)propane]disulfate dehydrate;2,2′-Azobis(1-imino-1-pyrrolidino-2-ethylpropane)dihydrochloride;2,2′-Azobis[2-methyl-N-(2-hydroxyethyl)propionamide];2,2′-Azobis(2-methylpropionamidine)dihydrochloride;2,2′-dicarboxymethoxydibenzalacetone,4,4′-dicarboxymethoxydibenzalacetone,4,4′-dicarboxymethoxydibenzalcyclohexanone,4-dimethylamino-4′-carboxymethoxydibenzalacetone; and4,4′-disulphoxymethoxydibenzalacetone. Other suitable photoinitiatorsthat can be used are listed in U.S. Pat. No. 4,824,765.

In addition to the previously described components other components maybe included in either the aqueous or oil phase of a HIPE. Examplesinclude antioxidants, for example hindered phenolics, hindered aminelight stabilizers; plasticizers, for example dioctyl phthalate, dinonylsebacate; flame retardants, for example halogenated hydrocarbons,phosphates, borates, inorganic salts such as antimony trioxide orammonium phosphate or magnesium hydroxide; dyes and pigments;fluorescers; filler particles, for example starch, titanium dioxide,carbon black, or calcium carbonate; fibers; chain transfer agents; odorabsorbers, for example activated carbon particulates; dissolvedpolymers; dissolved oligomers; and the like.

HIPE foam is produced from the polymerization of the monomers comprisingthe continuous oil phase of a HIPE. In certain examples, a HIPE foamlayer may have one or more sublayers, and may be either homogeneous orheterogeneous polymeric open-celled foams. Homogeneity and heterogeneityrelate to distinct layers within the same HIPE foam, which are similarin the case of homogeneous HIPE foams and differ in the case ofheterogeneous HIPE foams. A heterogeneous HIPE foam may contain at leasttwo distinct sublayers that differ with regard to their chemicalcomposition, physical properties, or both; for example, sublayers maydiffer with regard to one or more of foam density, polymer composition,specific surface area, or pore size (also referred to as cell size). Forexample, for a HIPE foam if the difference relates to pore size, theaverage pore size in the respective sublayers may differ by at leastabout 20%, in certain examples by at least about 35%, and in still otherexamples by at least about 50%. In another example, if the differencesin the sublayers of a HIPE foam layer relate to density, the densitiesof the layers may differ by at least about 20%, in certain examples byat least about 35%, and in still other examples by at least about 50%.For instance, if one layer of a HIPE foam has a density of 0.020 g/cm³,another layer may have a density of at least about 0.024 g/cm3 or lessthan about 0.016 g/cm3, in certain examples at least about 0.027 g/cm³or less than about 0.013 g/cm³, and in still other examples at leastabout 0.030 g/cm³ or less than about 0.010 g/cm³. If the differencesbetween the layers are related to the chemical composition of the HIPEor HIPE foam, the differences may reflect a relative amount differencein at least one monomer component, for example by at least about 20%, incertain examples by at least about 35%, and in still further examples byat least about 50%. For instance, if one sublayer of a HIPE or HIPE foamis composed of about 10% styrene in its formulation, another sublayer ofthe HIPE or HIPE foam may be composed of at least about 12%, and incertain examples of at least about 15%.

A HIPE foam layer structured to have distinct sublayers formed fromdiffering HIPEs may provide a HIPE foam layer with a range of desiredperformance characteristics. For example, a HIPE foam layer comprisingfirst and second foam sublayers, wherein the first foam sublayer has arelatively larger pore or cell size, than the second sublayer, when usedin an absorbent article may more quickly absorb incoming fluids than thesecond sublayer. For example, when the HIPE foam layer is used to forman absorbent structure 140 of a feminine hygiene pad, the first foamsublayer may be layered over the second foam sublayer having relativelysmaller pore sizes, as compared to the first foam sublayer, which exertmore capillary pressure and draw the acquired fluid from the first foamsublayer, restoring the first foam sublayer's ability to acquire morefluid from above. HIPE foam pore sizes may range from 1 to 200 μm and incertain examples may be less than 100 μm. HIPE foam layers of thepresent disclosure having two major parallel surfaces may be from about0.5 to about 10 mm thick, and in certain examples from about 2 to about10 mm. The desired thickness of a HIPE foam layer will depend on thematerials used to form the HIPE foam layer, the speed at which a HIPE isdeposited on a belt, and the intended use of the resulting HIPE foamlayer.

The HIPE foam layers of the present disclosure are preferably relativelyopen-celled. This refers to the individual cells or pores of the HIPEfoam layer being in substantially unobstructed communication withadjoining cells. The cells in such substantially open-celled HIPE foamstructures have intercellular openings or windows that are large enoughto permit ready fluid transfer from one cell to another within the HIPEfoam structure. For purpose of the present disclosure, a HIPE foam isconsidered “open-celled” if at least about 80% of the cells in the HIPEfoam that are at least 1 μm in size are in fluid communication with atleast one adjoining cell.

In addition to being open-celled, in certain examples HIPE foams areadapted to be sufficiently hydrophilic to permit the HIPE foam to absorbaqueous fluids. In some examples the internal surfaces of a HIPE foammay be rendered hydrophilic by residual hydrophilizing surfactants orsalts left in the HIPE foam following polymerization, or by selectedpost-polymerization HIPE foam treatment procedures such as those asdescribed in references cited herein.

In certain examples, for example when it is used to form an absorbentstructure 140 of a feminine hygiene pad, a HIPE foam layer may beflexible and exhibit an appropriate glass transition temperature (Tg).The Tg represents the midpoint of the transition between the glassy andrubbery states of the polymer. In general, HIPE foams that have a Tgthat is higher than the temperature of use can be strong but will alsobe relatively rigid and potentially prone to fracture (brittle). Incertain examples, regions of the HIPE foams of the current disclosurewhich exhibit either a relatively high Tg or excessive brittleness willbe discontinuous. Since these discontinuous regions will also generallyexhibit high strength, they can be prepared at lower densities withoutcompromising the overall strength of the HIPE foam.

HIPE foams intended for applications requiring flexibility shouldcontain at least one continuous region having a Tg as low as possible,so long as the overall HIPE foam has acceptable strength at in-usetemperatures. In certain examples, the Tg of this region will be lessthan about 40° C. for foams used at about ambient temperatureconditions; in certain other examples Tg will be less than about 30° C.For HIPE foams used in applications wherein the use temperature ishigher or lower than ambient temperature, the Tg of the continuousregion may be no more than 10° C. greater than the use temperature, incertain examples the same as use temperature, and in further examplesabout 10° C. less than use temperature wherein flexibility is desired.Accordingly, monomers are selected as much as possible that providecorresponding polymers having lower Tg's.

HIPE foams useful for forming absorbent structures and/or sublayerswithin contemplation of the present disclosure, and materials andmethods for their manufacture, also include but are not necessarilylimited to those foams and methods described in U.S. Pat. Nos.10,045,890; 9,056,412; 8,629,192; 8,257,787; 7,393,878; 6,551,295;6,525,106; 6,550,960; 6,406,648; 6,376,565; 6,372,953; 6,369,121;6,365,642; 6,207,724; 6,204,298; 6,158,144; 6,107,538; 6,107,356;6,083,211; 6,013,589; 5,899,893; 5,873,869; 5,863,958; 5,849,805;5,827,909; 5,827,253; 5,817,704; 5,817,081; 5,795,921; 5,741,581;5,652,194; 5,650,222; 5,632,737; 5,563,179; 5,550,167; 5,500,451;5,387,207; 5,352,711; U.S. Pat. Nos. 5,397,316; 5,331,015; 5,292,777;5,268,224; 5,260,345; 5,250,576; 5,149,720; 5,147,345; and US2005/0197414; US 2005/0197415; US 2011/0160326; US 2011/0159135; US2011/0159206; US 2011/0160321; US 2011/0160689, and U.S. App. Ser. No.62/804,864, which are incorporated herein by reference to the extent notinconsistent herewith.

An absorbent structure formed of HIPE foam may include one or morepatterns of perforations therethrough, including at least a firstpattern disposed within an expected discharge location overlying theintersection of longitudinal and lateral axes of the pad. Perforationsmay be punched, cut or otherwise formed through the entire z-directiondepth of the HIPE foam absorbent structure, or only through awearer-facing layer or partially into the wearer-facing portion thereof.When a HIPE foam absorbent structure is disposed in direct contact witha topsheet as described herein, with no intervening acquisition layerformed of another material, perforations therethrough may serve as agroup of reservoirs to receive, temporarily hold, and aid indistributing rapid discharges of relatively small quantities ofmenstrual fluid, until the HIPE foam has sufficient time to distributeand absorb the fluid via capillary action. Additionally, suchperforations help decrease bending stiffness of the absorbent structure,which may help increase comfort of the pad for the wearer. A pattern ofperforations having an average radius or other largest dimension of 1.0mm to 4.0 mm, and more preferably 1.5 mm to 3.5 mm may be included. Thepattern may include perforations at a numerical density of 3.0 to 9.0perforations per cm², and more preferably 4.0 to 8.0 perforations percm². In selecting the appropriate average size, numerical density, andsurface area occupied by the pattern of perforations, the manufacturermay wish to balance the volume of the “reservoirs” desired with the needto retain absorbent material in locations proximate to and about theexpected discharge location. Additional details concerningconfigurations of such perforations in combination with examples ofsuitable absorbent structures may be found in U.S. Pat. No. 8,211,078.

An absorbent structure formed of HIPE foam should be imparted withsufficient size, capillarity and hydrophilicity to have capability toeffectively draw discharged fluid from a topsheet over a time ofuse/wear of the pad during menstruation that is normal and expected forfeminine hygiene pads, for example, from 4 to 8 hours. Thus, it may bedesired that an absorbent structure 140 formed of HIPE foam have acaliper (prior to wetting) that provides satisfactory absorbency to astandard-sized pad. Of course, a relatively thick pad can bemanufactured, but that is typically deemed undesirable for daytime usein view of desires for flexibility/pliability and thinness, for comfortand discreetness under clothing. The manufacture must balance thesecompeting objectives. Accordingly a feminine hygiene pad with a HIPEfoam absorbent structure as contemplated herein, it may be desired thatthe layer have a caliper in the majority of its wearer-facing surfacearea (prior to wetting) of 1 mm to 5 mm, or more preferably 1.5 mm to3.5 mm, or even more preferably 2.0 mm to 3.0 mm. (The caliper of a HIPEfoam layer may be measured visually, with assistance ofmagnification/microscopy and/or photography or any other facilitatingtechniques and equipment, to any extent deemed useful.) Where theabsorbent structure 140 includes two sublayers as described herein, itmay be desired that the upper sublayer have a caliper (prior to wetting)of 0.64 mm to 3.2 mm, or preferably 0.96 mm to 2.24 mm, or even morepreferably 1.28 mm to 1.92 mm; and it may be desired that the lowersublayer have a caliper (prior to wetting) of 0.16 mm to 0.80 mm, ormore preferably 0.24 mm to 0.56 mm, or even more preferably 0.32 mm to0.48 mm.

In other examples, the absorbent structure may be a heterogeneous massformed of a nonwoven layer of spun filaments, with discrete foam pieceswithin and interspersed/distributed through the nonwoven structure, thediscrete foam pieces being formed about and enrobing portions offilaments. Examples of such an absorbent structure are described in U.S.Pat. Nos. 10,045,890; 10,016,779; 9,956,586; 9,993,836; 9,574,058; US2015/0313770; US 2015/0335498; US 2015/0374876; US 2015/0374561; US2016/0175787; US 2016/0287452; US 2017/0071795; US 2017/0119587; US2017/0119596; US 2017/0119597; US 2017/0119588; US 2017/0119593; US2017/0119594; US 2017/0119595; US 2017/0199598; US 2017/0267827; US2018/0110660; US 2017/0119600; US 2017/0119589; US 2018/0169832; US2018/0168884; and US 2018/0318150.

The absorbent structure may also include similar optional layers. Theymay be webs selected from the group consisting of a fibrous structure,an airlaid web, a wet laid web, a high loft nonwoven, a needlepunchedweb, a hydroentangled web, a fiber tow, a woven web, a knitted web, aflocked web, a spunbond web, a layered spunbond/melt blown web, a cardedfiber web, a coform web of cellulose fiber and melt blown filaments, acoform web of staple fibers and melt blown filaments, and layered websthat are layered combinations thereof.

These optional layers of the core and of the chassis may includematerials such as creped cellulose wadding, fluffed cellulose fibers,airlaid (airfelt), and textile fibers. The materials of the optionallayers may also include filaments such as, for example, synthetic fibersor filaments, thermoplastic particulates, fibers or filaments,tricomponent filaments, and bicomponent fibers or filaments such as, forexample, sheath/core filaments having, for example, any of the followingpolymer combinations: polyethylene/polypropylene, polyethylvinylacetate/polypropylene, polyethylene/polyester, polypropylene/polyester,copolyester/polyester, and the like. The optional layers may include anycombination of the materials listed above, copolymers thereof, and/or aplurality of the materials listed above, alone or in combination.

The materials of the optional layers may be hydrophobic or hydrophilicdepending on their functions and placement within or relative to theabsorbent structure.

The materials of the optional layers may be formed of constituent fibersor filaments including polymers such as polyethylene, polypropylene,polyester, copolymers thereof, and blends thereof. Filaments may beformed in a spunbond process. Filaments may be formed in a meltblowingprocess. Fibers or filaments may also be formed of or include cellulose,rayon, cotton, or other natural materials or blends of polymeric andnatural materials. The fibers or filaments may also include asuperabsorbent material such as polyacrylate or any combination ofsuitable materials. The fibers or filaments may be monocomponent,bicomponent, and/or biconstituent, non-round (e.g., capillary channelfibers), and may have major cross-sectional dimensions (e.g., diameterfor round fibers) ranging from 0.1-500 microns. The constituent fibersor filaments of the nonwoven precursor web may also be a mixture ofdifferent types, differing in such features as chemistry (e.g.polyethylene and polypropylene), components (mono- and bi-), denier(micro denier and >20 denier), shape (i.e., capillary and round) and thelike. The constituent fibers or filaments may range from about 0.1denier to about 100 denier.

The optional layers may include thermoplastic particulates, fibers orfilaments. The materials, and in particular thermoplastic fibers orfilaments, may be made from a variety of thermoplastic polymersincluding polyolefins such as polyethylene and polypropylene,polyesters, copolyesters, and copolymers of any of the foregoing.

Depending upon the desired characteristics, suitable thermoplasticmaterials include hydrophobic fibers that have been made hydrophilic,such as surfactant-treated or silica-treated thermoplastic fibers orfilaments derived from, for example, polyolefins such as polyethylene orpolypropylene, polyacrylics, polyamides, polystyrenes, and the like. Thesurface of the hydrophobic thermoplastic fiber or filament may berendered hydrophilic by treatment with a surfactant, such as a nonionicor anionic surfactant, e.g., by spraying the fiber or filament with asurfactant, by dipping the fiber or filament into a surfactant or byincluding the surfactant as part of the polymer melt in producing thethermoplastic fiber. Upon melting and resolidification, the surfactantwill tend to remain at the surfaces of the thermoplastic fiber orfilament. Suitable surfactants include nonionic surfactants such as BRIJ76 manufactured by ICI Americas, Inc. of Wilmington, Del., and varioussurfactants sold under the PEGOSPERSE by Glyco Chemical, Inc. ofGreenwich, Conn. Besides nonionic surfactants, anionic surfactants mayalso be used. These surfactants may be applied to the thermoplasticfibers at levels of, for example, from about 0.2 to about 1 g/cm² ofthermoplastic fiber or filament.

Suitable thermoplastic filaments may be made from a single polymer(monocomponent filaments), or may be made from more than one polymer(e.g., bicomponent filaments). Suitable bicomponent fibers for use instructures contemplated herein may include fibers with components havinga sheath/core configuration, eccentric sheath/core configuration orside-by-side configuration. Side-by-side or eccentric sheath/coreconfigurations may be preferred rather than coaxial sheath/coreconfigurations because of their tendency to impart curl or crimp to thespun filaments resulting from differing contraction rates of thecomponents upon cooling following spinning. This may be preferred insome circumstances because crimped or curled constituent filaments willimpart greater loft to the web than uncrimped/uncurled filaments, andimpart the web with greater perceivable softness and comfort attributes;such circumstances may include, for example, when the finished nonwovenweb product is to be manufactured with a relatively low basis weightthat would otherwise result in a relatively thin (low-caliper) product.Polymeric components may include any of the following combinations:polyethylene/polypropylene, polyethylvinyl acetate/polypropylene,polyethylene/polyester, polypropylene/polyester, copolyester/polyester,and the like. Particularly suitable bicomponent thermoplastic fibers foruse herein are those having a polypropylene or polyester core, and alower melting copolyester, polyethylvinyl acetate or polyethylene sheath(e.g., DANAKLON, CELBOND, or CHISSO bicomponent fibers).

The optional layers may also include synthetic fibers or filaments thattypically do not contribute to bonding but alter the mechanicalproperties of the fibrous webs. Such synthetic fibers or filaments mayfibers or filaments formed of cellulose acetate, polyvinyl fluoride,polyvinylidene chloride, acrylics (such as Orlon), polyvinyl acetate,non-soluble polyvinyl alcohol, polyethylene, polypropylene, polyamides(such as nylon), polyesters, and mixtures thereof. These might include,for example, polyesters such as polyethylene terephthalate (e.g.,DACRON, and KODEL), high melting polyester (e.g., KODEL 431 made byEastman Chemical Co.) hydrophilic nylon (HYDROFIL), and the like.Suitable fibers or filaments may also hydrophilized hydrophobic, forexample, by surfactant- or silica-treating. In the case of nonbondingthermoplastic fibers, their length may vary depending upon theparticular properties desired for these fibers. Typically they have alength from about 0.3 to 7.5 cm, such as, for example from about 0.9 toabout 1.5 cm. Suitable nonbonding thermoplastic fibers may have adecitex in the range of about 1.5 to about 35 decitex, such as, forexample, from about 14 to about 20 decitex.

Adjusting Topsheet Surface Chemistry for Hydrophilicity

Referring to FIG. 20, the functions of a topsheet formed as describedherein may be enhanced by adding hydrophilic material to the formednonwoven web material at select locations. In some examples, asurfactant may be selectively applied to the absorbent-facing surface123 of the topsheet material. In a more particular example, asurfactant, or solution or emulsion containing a surfactant, may beapplied to an absorbent-facing side of the topsheet material via, forexample, use of a kiss roll coater, spray application, printingtechnique, or any other suitable liquid deposition technique, to depositan application of surfactant or solution or emulsion containing asurfactant 282 to the material. Under suitable conditions includingsuitable disposition of filaments and/or fibers in nonwoven webmaterial, and process techniques/conditions, filaments and/or fibersand/or portions thereof occupying and defining the absorbent-facingsurface 123 of the topsheet material and the bottoms of the channelportions 164 will have the surfactant applied to them, while filamentsand/or fibers and/or portions thereof occupying and defining thewearer-facing surface 124, and built-up regions 166 thereof will havelittle or no applied surfactant on their wearer-facing surfaces, suchthat the surfactant is present in a quantity greater on filamentsproximate the absorbent-facing side than on filaments proximate thewearer-facing side. In the resulting topsheet, aqueous fluid (liquidbody exudate) may be more likely to flow in and along the channels 164and/or drain into discrete low bulk portions 165, and through the bottomportions thereof generally along a z-direction, to reach absorbentmaterial disposed below the topsheet in the absorbent article, and thebuilt-up regions 166 adjacent the attenuated regions 163, having arelatively greater number of hydrophobic filaments and/or fibers, maytend to slow or block passage of aqueous fluid along the wearer-facingsurface 124, along an x-y plane toward the outer perimeter 128 of thein-use wearer-facing portion 126 of the topsheet. It will be appreciatedthat, to refine or enhance the desired fluid channeling/barrier and/ordraining effect, surfactant application techniques and equipment may beadapted to selectively apply surfactant to limited or defined portionsof the section(s) of nonwoven web material forming the topsheet. Forexample, surfactant may be applied only to portions of theabsorbent-facing surface 123 lying to the inside of one or more of thechannel portions 164 (with respect to an x-y plane occupied by thematerial), or to portions of the absorbent-facing surface 123 that doesnot include wing portions 114, etc. Where the nonwoven is predominatelyformed of polypropylene, in a non-limiting example, a surfactantsuitable for application via MSS roll equipment or alternatively inkjetprinting equipment may include STANTEX S6887 surfactant spin finish, aproduct of Pulcra Chemicals/Fashion Chemicals GmbH & Co., Geretsried,Germany.

Referring to FIG. 21, in another example, for effects similar to thosedescribed immediately above, a nonwoven web material formed as describedherein may be coupled via bonding or otherwise with a second layer 281of filaments and/or fibers formed of hydrophilic material, to form theabsorbent-facing surface of the topsheet. In some examples, this secondlayer 281 may be a second, separately manufactured web material. Inother examples, this second layer 281 may be a deposit of filamentsand/or fibers deposited over the primary (hydrophobic) filaments and/orfibers forming the built-up regions 166 and channel portions 164 and thewearer-facing surface 124, during the same web manufacturing process.

Coloration

Polymer component resins to be melt spun may include coloring agentssuch as tinting or pigmenting agents, and/or whitening and/or opacifyingagents. In some examples, all of the filaments and/or fibers forming thenonwoven web material may be tinted or pigmented. Alternatively, asecond layer 281, of nonwoven material, or of deposited, spun filamentsand/or fibers may also include filaments and/or fibers spun from polymerresin blended with a tinting and/or pigmenting agent, to impart a colorto the filaments and/or fibers that contrasts with the color of thefilaments and/or fibers in first layer 280 a. This may be desired forenhancing the visual impact of the ordered arrangement of changes infiber and/or filament area density and basis weight between theattenuated regions 163 and the built-up regions 166 (see descriptionbelow) of the web material. In one non-limiting example, filamentsand/or fibers of the first layer 280 a may include no tinting orpigmenting agents, while filaments and/or fibers of the second layer 281may include one or more tinting or pigmenting agents. In anothernon-limiting example, filaments and/or fibers of the first layer 280 amay include a whitening and/or opacifying agent (such as, for example,TiO₂), and filaments and/or fibers of the second layer may include acoloring agent such as a non-white pigmenting or tinting agent. It willbe appreciated that these and other combinations of tinting, whitening,opacifying and/or pigmenting agents may be used to impart visible colorcontrast between first and second layers forming the web material. Instill other examples, underlying materials such as materials forming theabsorbent structure and/or the backsheet may include whitening, tintingor pigmenting agents selected to provide visual contrast with thetopsheet.

Pigmenting, whitening and/or opacifying agents may be obtainedpre-dispersed in carrier resins, in color masterbatch products suitablefor blending with filament component resin(s) prior to or duringintroduction into the extruder(s). The agent(s) selected are preferablysolid, powdered compositions that do not dissolve in or react chemicallywith the polymer resins when blended and dispersed within the filamentcomponent resins as they are melted, extruded and spun into filamentsunder ordinary melt-spinning process conditions. Suitable pigmentingagents may include solid inorganic or organic compositions, and in someexamples may be solid organometallic compositions.

Suitable white pigment masterbatch products typically include solidmetallic and/or organometallic compositions, for example, AntimonyWhite, Barium Sulfate, Lithopone, Cremnitz White, Titanium White (TiO₂),and Zinc White (ZnO).

In some examples, filaments forming the finished, formed nonwoven webmaterial 280, or at least a first layer 280 a thereof, may be spun frompolymer resin(s) to which a blue pigmenting agent has been added. Theinventors believe that an appropriate concentration of blue pigmentadded to the filament component resin may have a dramatic impact onvisibility of the variances in basis weight and caliper in the orderedarrangement, enhancing the appearance of z-direction depth and overallthree-dimensional structure. Without intending to be bound by theory,the inventors believe that other single pigments or combinations ofpigments, admixed with the filament resin(s) to select weight percentconcentrations, may have a similar effect on enhancing the visibility ofapparent depth and/or visibility of three-dimensional structuralfeatures of the nonwoven web 280.

Suitable blue pigment masterbatch products typically also include solidmetallic and/or organometallic compositions, for example, Ultramarine,Persian Blue, Cobalt Blue, Cerulean Blue, Egyptian Blue, Han Blue,Azurite, Prussian Blue, YImMn Blue and Manganese Blue. In a particularexample, a blue color masterbatch product may be admixed to aconcentration of approximately 0.25% of total weight polypropylenefilament spinning resin, where the masterbatch product comprisesapproximately 36% by weight blue pigment composition. It is believedthat an effective weight percent concentration of blue pigment materialwithin the total spinning resin blend, for purposes of enhancingvisibility of apparent depth and/or visibility of three-dimensionalstructural features of the nonwoven web 280 as described above, may befrom approximately 0.03 percent to approximately 0.15 percent, morepreferably from approximately 0.06 percent to 0.12 percent.

In yet another approach, an ink of a non-white color or color thatcontrasts with the spun filament color, may be applied via any suitabletechnique to the surface of the nonwoven web material that will becomethe absorbent-facing surface of a topsheet, to enhance visual impact asdescribed above.

Process for Manufacturing Topsheet Material

Formed nonwoven web material from which topsheets as described above maybe formed using equipment, processes and materials described in, forexample, any of US application pub. nos. US 2017/0191198; US2017/0029994; US 2017/0029993 and US 2017/0027774, and U.S. applicationSer. Nos. 15/840,455; 15/879,474; 15/879,477; 15/881,910; 62/527,216;62/527,224, 62/819,729; and 62/819,744, the disclosures of which areincorporated by reference herein.

Formed nonwoven web materials may be manufactured from spun filaments ina spunbond process, utilizing a specially adapted forming belt. Thetopsheet may be formed predominately of spunbond filaments orsubstantially entirely of spunbond filaments. Additional web loft andmanufacturing efficiency may be achieved when the topsheet is formed ofspunbond, bicomponent filaments. Bicomponent filaments may spun so as tohave a side-by-side bicomponent configuration, such that suitableselection of differing resin components will impart crimp or curl to thefilaments as they cool; crimp or curl of the filaments can helpcontribute to loft of the resulting web.

Topsheet Formation Process Components

For example, referring to FIG. 11, a process line 500 for manufacturinga formed nonwoven web material of bicomponent filaments may include apair of melt extruders 532 and 534, driven by extruder drives 531 and533, respectively, for separately melting and extruding a first polymercomponent resin and a second polymer component resin. The first polymercomponent resin may be fed into the respective extruder 532 from a firsthopper 536 and the second polymer component resin may be fed into therespective extruder 534 from a second hopper 538. The first and secondpolymer component resins may melted and driven by the extruders 532 and534 through respective polymer conduits 540 and 542 then through filters544 and 545, to melt pumps 546 and 547, which help pump the polymer intoand through a spin pack 548. Spin packs with spinnerets used in spinningbicomponent filaments are known in the art and therefore are notdescribed here in great detail.

Generally described, a spin pack 548 may include a housing whichincludes a plurality of plates stacked one on top of the other with apattern of openings arranged to create flow paths for directing themelted first and second polymer component resins separately throughspinneret openings. The spin pack 548 may have spinneret openingsarranged in one or more rows. As the melted polymer resins are forcedthrough them, the spinneret openings emit a downward curtain ofindividual melted polymer streams 122 a. For the purposes of the presentdisclosure, spinnerets may be arranged to form streams for sheath/coreor side-by-side bicomponent filaments. Bicomponent filaments may bepreferred in some circumstances for their particular characteristics.Side-by-side or eccentric or asymmetric core/sheath bicomponentfilaments may be preferred where it is desired that the spun filamentshave a spiral or curl imparted by differing cooling contraction rates ofdiffering components, wherein spiral or curl in the spun filaments maycontribute to enhanced loft and bulk of the nonwoven web material.Core/sheath bicomponent filaments may be preferred where it is desiredthat the respective components have differing attributes or propertiesthat might be advantageously balanced. Such attributes or propertiesmight include raw material (resin) cost, or spun tensile strength, orsurface feel or surface friction. In one example, a core/sheath filamentin which the core component is predominately polypropylene and thesheath component is predominately polyethylene may be preferred, whereinpolypropylene is selected for the core component for its relativelylower cost and contribution to filament tensile strength, andpolyethylene is selected for the sheath component for a relatively lowermelting point (for purposes of thermal bonding between filaments) and arelatively lower-friction, silkier feel it imparts to the filamentsurfaces.

Although the above description contemplates spinning bicomponentfilaments, it will be appreciated that the equipment and materialssupplied may be adapted, selected and configured to spin monocomponentfilaments, or multicomponent filaments having more than two components.

Spinnerets may be configured and adapted to form streams with generallycircular cross-sections (to form filaments with generally round/circularcross sections), or streams with generally non-round cross sections suchas asymmetric, multi-lobal, e.g., trilobal cross sections (to formasymmetric, lobed, e.g., trilobal filaments). Lobed filaments may bedesired in some circumstances for their effects on fluid flow alongtheir surfaces, for their effects on filament and nonwoven opacity, fortheir effects on fiber and nonwoven feel, or a combination of theseeffects. Generally, a nonwoven web material formed of lobed filamentssuch as trilobal filaments has greater opacity than an otherwisecomparable nonwoven web material formed of round filaments, as a resultof greater light refraction and/or diffusion through trilobal filaments.Fluid flow along filament surfaces may be enhanced or inhibited to agreater extent by lobed cross sections, depending upon whether thesurfaces of the filaments are hydrophilic or hydrophobic, respectively.

The process line 530 also may include a quench blower 550 positionedbeneath/adjacent the location the polymer streams 122 a exit thespinnerets. Temperature, velocity and direction of air from the quenchair blower 550 may be suitably controlled to quench the polymer streams,causing them to partially solidify. Quench air may be provided anddirected at one (upstream or downstream) side of the curtain or bothsides of the curtain.

An attenuator 552 may be positioned below the spinneret to receive thequenched polymer streams 122 a. Filament draw units or aspirators foruse as attenuators in melt spinning polymers are known in the art.Suitable filament draw units for use in the process of the presentdisclosure may include a linear filament attenuator of the type shown inU.S. Pat. No. 3,802,817, or eductive guns of the type shown in U.S. Pat.Nos. 3,692,618 and 3,423,266, the disclosures of which are incorporatedherein by reference.

Generally, the attenuator 552 may include and define an elongatevertical passage through which the polymer streams 122 a may beentrained in a downward air stream, drawn downward, elongated andreduced in cross section to form filaments 122. A shaped, at leastpartially foraminous forming belt 260 is positioned below the attenuator552 and receives the downward-moving continuous filaments from theoutlet opening of the attenuator 552. The forming belt 260 is acontinuous belt, having an outer receiving side 260 a and an inner side260 b, and cycles about guide rollers 562, one or more of which may bedriven at a controlled speed to cause the belt to translate along an x-yplane and along a machine direction MD through a working location 561beneath the attenuator. A forming vacuum system 555 may be positionedbelow the working location 561 of the belt 260 where the filaments aredeposited, to draw the air of the air stream through the belt, andthereby draw the entrained filaments toward and against the beltsurface. Although the forming belt 260 is shown and described as a beltherein, it will be understood that a forming device with a suitableforming surface may also have other forms, such as a rotatable drum witha suitable cylindrical forming surface. Features of examples of shapedforming belts are described below.

In operation of the process line 500, the hoppers 536 and 538 may besupplied with the respective desired first and second polymer componentresin(s). First and second polymer component resin(s) may be melted bythe respective extruders 532 and 534, and forced in their melted statethrough polymer conduits 540 and 542 to spin pack 548. The line mayinclude filters 544, 545 to filter out solid impurities from the meltedresins, and the line may also include supplemental melt pumps 546, 547to increase pressure in the conduits and thereby assist in driving thepolymer components to and through the spin pack 548. Although thetemperatures of the melted polymer resins can be controlled and variedfor the polymers used and desired process conditions, when one or bothof polyethylene and polypropylene are predominately the componentresins, the temperatures of the melted polymer resins may be controlledto be within a range from about 190 deg. C. to about 240 deg. C.

Topsheet Filament Spinning Resin Formulation

Non-limiting examples of particularly suitable polymeric resins forspinning bicomponent filaments contemplated herein include PH835polypropylene obtained from LyondellBasell (Rotterdam, Netherlands) andAspun-6850-A polyethylene obtained from Dow Chemical Company (Midland,Mich., USA). Although polypropylene and polyethylene are contemplated aspredominant polymer resin constituents for spinning filaments, for theirthermodynamic and mechanical attributes combined with their costs at thepresent time, a wide variety of polymers may be suitable for use withinthe scope of the present disclosure. Other suitable examples includePP3155 and ACHIEVE 3854 products available from ExxonMobil, Irving, Tex.

Non-limiting examples of potentially suitable synthetic polymers includethermoplastic polymers, such as polyesters, nylons, polyamides,polyurethanes, polyolefins (such as polypropylene, polyethylene andpolybutylene), polyvinyl alcohol and polyvinyl alcohol derivatives,sodium polyacrylate (absorbent gel material), and copolymers ofpolyolefins such as polyethylene-octene or polymers comprising monomericblends of propylene and ethylene, and biodegradable or compostablethermoplastic polymers such as polylactic acid, polyvinyl alcohol, andpolycaprolactone. Potentially suitable natural polymers include starch,starch derivatives, cellulose and cellulose derivatives, hemicellulose,hemicelluloses derivatives, chitin, chitosan, polyisoprene (cis andtrans), peptides and polyhydroxyalkanoates. In one example, apredominate polymer component for spinning filaments may be athermoplastic polymer selected from the group consisting of:polypropylene, polyethylene, polyester, polylactic acid,polyhydroxyalkanoate, polyvinyl alcohol, polycaprolactone,styrene-butadiene-styrene block copolymer, styrene-isoprene-styreneblock copolymer, polyurethane, and mixtures thereof. In another example,the thermoplastic polymer may be selected from the group consisting of:polypropylene, polyethylene, polyester, polylactic acid,polyhydroxyalkanoate, polyvinyl alcohol, polycaprolactone, and mixturesthereof. Alternatively, the polymer may comprise one derived frommonomers which are partially produced by biological processes, such asbio-polyethylene or bio-polypropylene.

In some circumstances it may be desired to manipulate and/or the enhancefeatures of the spun filaments such as color, opacity, pliability,hydrophilicity/hydrophobicity and/or surface feel (e.g., surfacecoefficient of friction) of fibers spun from the component resin(s). Insuch circumstances one or more melt additives may be included with theresin(s) fed to the extruder(s).

Inorganic fillers such as the oxides of magnesium, aluminum, silicon,and titanium may be added to the polymer resins as whiteners,opacifiers, fillers or processing aides. Other inorganic materialsinclude hydrous magnesium silicate, titanium dioxide, calcium carbonate,clay, chalk, boron nitride, limestone, diatomaceous earth, mica glassquartz, and ceramics.

Topsheet Filament Surface Property Manipulation

Slip agent melt additives may be included in an amount sufficient toaffect and/or enhance desired haptic properties (e.g., impart asoft/silky/slick feel) to the filaments. Some slip agents whenmelt-blended with the resin gradually migrate to the filament surfacesduring cooling or after fabrication, hence forming a thin coating withlubricating effects, in the filament surfaces. It may be desired thatthe slip agent be a fast-bloom slip agent, and can be a hydrocarbonhaving one or more functional groups selected from hydroxide, aryls andsubstituted aryls, halogens, alkoxys, carboxylates, esters, carbonunsaturation, acrylates, oxygen, nitrogen, carboxyl, sulfate andphosphate. In one particular form, the slip agent is a salt derivativeof an aromatic or aliphatic hydrocarbon oil, notably metal salts offatty acids, including metal salts of carboxylic, sulfuric, andphosphoric aliphatic saturated or unsaturated acid having a chain lengthof 7 to 26 carbon atoms, preferably 10 to 22 carbon atoms. Examples ofsuitable fatty acids include the monocarboxylic acids lauric acid,stearic acid, succinic acid, stearyl lactic acid, lactic acid, phthalicacid, benzoic acid, hydroxystearic acid, ricinoleic acid, naphthenicacid, oleic acid, palmitic acid, erucic acid, and the like, and thecorresponding sulfuric and phosphoric acids. Suitable metals include Li,Na, Mg, Ca, Sr, Ba, Zn, Cd, Al, Sn, Pb and so forth. Representativesalts include, for example, magnesium stearate, calcium stearate, sodiumstearate, zinc stearate, calcium oleate, zinc oleate, magnesium oleateand so on, and the corresponding metal higher alkyl sulfates and metalesters of higher alkyl phosphoric acids.

In other examples, the slip agent may be a non-ionic functionalizedcompound. Suitable functionalized compounds include: (a) esters, amides,alcohols and acids of oils including aromatic or aliphatic hydrocarbonoils, for example, mineral oils, naphthenic oils, paraffinic oils;natural oils such as castor, corn, cottonseed, olive, rapeseed, soybean,sunflower, other vegetable and animal oils, and so on. Representativefunctionalized derivatives of these oils include, for example, polyolesters of monocarboxylic acids such as glycerol monostearate,pentaerythritol monooleate, and the like, saturated and unsaturatedfatty acid amides or ethylenebis(amides), such as oleamide, erucamide,linoleamide, and mixtures thereof, glycols, polyether polyols likeCarbowax, and adipic acid, sebacic acid, and the like; (b) waxes, suchas carnauba wax, microcrystalline wax, polyolefin waxes, for examplepolyethylene waxes; (c) fluoro-containing polymers such aspolytetrafluoroethylene, fluorine oils, fluorine waxes and so forth; and(d) silicon compounds such as silanes and silicone polymers, includingsilicone oils, polydimethylsiloxane, amino-modifiedpolydimethylsiloxane, and so on.

Fatty amides that may be useful for purposes of the present disclosureare represented by the formula: RC(O)NHR¹, where R is a saturated orunsaturated alkyl group having 7 to 26 carbon atoms, preferably 10 to 22carbon atoms, and R1 is independently hydrogen or a saturated orunsaturated alkyl group having from 7 to 26 carbon atoms, preferably 10to 22 carbon atoms. Compounds according to this structure include forexample, palmitamide, stearamide, arachidamide, behenamide, oleamide,erucamide, linoleamide, stearyl stearamide, palmityl palmitamide,stearyl arachidamide and mixtures thereof.

Ethylenebis(amides) that may be useful for purposes of the presentdisclosure are represented by the formula:

RC(O)NHCH₂CH₂NHC(O)R,

where each R is independently is a saturated or unsaturated alkyl grouphaving 7 to 26 carbon atoms, preferably 10 to 22 carbon atoms. Compoundsaccording to this structure include for example,stearamidoethylstearamide, stearamidoethylpalmitamide,palmitamidoethylstearamide, ethylenebisstearamide, ethylenebisoleamide,stearylerucamide, erucamidoethylerucamide, oleamidoethyloleamide,erucamidoethyloleamide, oleamidoethylerucamide,stearamidoethylerucamide, erucamidoethylpalmitamide,palmitamidoethyloleamide and mixtures thereof.

Commercially available examples of fatty amides include Ampacet 10061(Ampacet Corporation, White Plains, N.Y., USA) which comprises 5 percentof a 50:50 mixture of the primary amides of erucic and stearic acids inpolyethylene; Elvax 3170 (E.I. du Pont de Nemours and Company/DuPontUSA, Wilmington, Del., USA) which comprises a similar blend of theamides of erucic and stearic acids in a blend of 18 percent vinylacetate resin and 82 percent polyethylene. Slip agents also areavailable from Croda International Plc (Yorkshire, United Kingdom),including Crodamide OR (an oleamide), Crodamide SR (a stearamide),Crodamide ER (an erucamide), and Crodamide BR (a behenamide); and fromCrompton, including Kemamide S (a stearamide), Kemamide B (abehenamide), Kemamide O (an oleamide), Kemamide E (an erucamide), andKemamide (an N,N′-ethylenebisstearamide). Other commercially availableslip agents include Erucamid ER erucamide.

Other suitable melt additives for softness/reduction of the coefficientof friction include erucamide, stearamide, oleamide, and silicones e.g.polydimethylsiloxane. Some specific examples include CRODAMIDE slip &anti-block agents from Croda International Plc (Yorkshire, UnitedKingdom), and slip BOPP agents from Ampacet Corporation (White Plains,N.Y., USA). Some additional specific examples of softness/reduction ofthe coefficient of friction melt additives specifically tailored forpolypropylene are available from Techmer PM Company (Clinton, Tenn.,USA).

Nonwoven web materials within contemplation of the present disclosuremay include slip agents/softness melt additives independently, or inconjunction with other additives that affect the surface energy(hydrophilicity/hydrophobicity), or in conjunction with other filamentfeature variations including but not limited to filament size, filamentcross-sectional shape, filament cross-sectional configuration, and/orcurled filament variations. For examples of nonwoven web materialsincluding two or more web layers, or two or more deposited layers ofdiffering filaments, additives may be included in filaments of one layerbut not the other, or differing additives may be included in filamentsof differing layers.

As noted herein, in some examples it may be desired that filamentspresent at and proximate to the absorbent-facing surface 123 of thetopsheet have hydrophilic surface energy properties. To impart thefilaments with such properties, they may be spun from one or moreresin(s) inherently having such properties, or alternatively, they maybe spun from resin(s) blended with a melt additive that renders theresulting spun filaments hydrophilic. Alternatively, after spinning, thefilaments, the batt or the finished web may be treated with a materialsuch as a surfactant renders them hydrophilic. This may be desired forpurposes of selectively imparting portions of the topsheet (such as theabsorbent-facing surface 123) with hydrophilicity, to affect its fluidhandling characteristics.

In conjunction therewith, it may be desired that filaments presentwithin the topsheet at locations more removed from the absorbent-facingsurface 123, including filaments present at and proximate to thewearer-facing surface 124, be spun from inherently hydrophobic resin, oradditionally or alternatively, be spun from resin blended with a meltadditive that renders the resulting spun filaments hydrophobic, orenhances hydrophobicity. Inherent and/or enhanced hydrophobicity offilaments as spun may help prevent unwanted migration of an appliedsolution, emulsion or concentrate of surfactant in a z-direction fromthe absorbent-facing surface toward the wearer-facing surface, and mayalso enhance the capability of the filaments in built-up regions 166 ofthe topsheet to serve as barriers to migration of aqueous body exudateacross the topsheet along a direction in the x-y plane, toward the outeredges of the pad. Hydrophobicity of filaments may be enhanced viaaddition of hydrophobizing melt additives to the resin(s) from which thefilaments are to be spun.

In some examples, a hydrophobizing melt additive may be added directlyor as master batch to the polymer melt during the spinning process.Suitable melt additives may include, for example, lipid esters orpolysiloxanes. When a hydrophobizing melt additive is blended intoresin(s), the additive in the resulting spun filament can bloom to itsexternal surface and create a film covering portions of the surface,form fibrils, flakes, particles, or other surface features that have lowsurface energy.

Any suitable hydrophobizing melt additive may be utilized. Examples ofhydrophobizing melt additives include fatty acids and fatty acidderivatives. The fatty acids may originate from vegetable, animal,and/or synthetic sources. Some fatty acids may range from a C8 fattyacid to a C30 fatty acid, or from a C12 fatty acid to a C22 fatty acid.In other forms, a substantially saturated fatty acid may be used,particularly when saturation arises as a result of hydrogenation offatty acid precursor. Examples of fatty acid derivatives include fattyalcohols, fatty acid esters, and fatty acid amides. Suitable fattyalcohols (R—OH) include those derived from C12-C28 fatty acids.

Suitable fatty acid esters include those fatty acid esters derived froma mixture of C12-C28 fatty acids and short chain (C1-C8, preferablyC1-C3) monohydric alcohols preferably from a mixture of C12-C22saturated fatty acids and short chain (C1-C8, preferably C1-C3)monohydric alcohols. The hydrophobizing melt additive may comprise amixture of mono, di, and/or tri-fatty acid esters. An example includesfatty acid ester with glycerol as the backbone as illustrated inillustration [1], below:

where R1, R2, and R3 each is an alkyl ester having carbon atoms rangingfrom 11 to 29. In some forms, the glycerol derived fatty acid ester hasat least one alkyl chain, at least two, or three chains to a glycerol,to form a mono, di, or triglyceride. Suitable examples of triglyceridesinclude glycerol thibehenate, glycerol tristearate, glyceroltripalmitate, and glycerol trimyristate, and mixtures thereof. In thecase of triglycerides and diglycerides, the alkyl chains could be thesame length, or different length. Example includes a triglyceride withone alkyl C18 chain and two C16 alkyl chain, or two C18 alkyl chains andone C16 chain. Preferred triglycerides include alkyl chains derived fromC14-C22 fatty acids.

Suitable fatty acid amides include those derived from a mixture ofC12-C28 fatty acids (saturated or unsaturated) and primary or secondaryamines. A suitable example of a primary fatty acid amide includes thosederived from a fatty acid and ammonia as illustrated in illustration[2], below:

where R has a number of carbon atoms ranging from 11 to 27. In at leastone other form, the fatty acids may range from a C16 fatty acid to a C22fatty acid. Some suitable examples include erucamide, oleamide andbehanamide. Other suitable hydrophobizing melt additives includehydrophobic silicones. Additional suitable hydrophobizing melt additivesare disclosed in U.S. patent application Ser. No. 14/849,630 and U.S.patent application Ser. No. 14/933,028. Another suitable hydrophobizingmelt additive is available from Techmer PM in Clinton, Tenn. under thetrade name PPM17000 High Load Hydrophobic. One specific example of ahydrophobizing melt additive is glycerol tristearate. As used herein,glycerol tristearate is defined as a mixture of long-chainedtriglycerides containing predominately C18 and C16 saturated alkyl chainlengths. Additionally, there could be varying degrees of unsaturationand cis to trans unsaturated bond configurations. The alkyl chainlengths could range from about C10 to about C22. The degrees ofunsaturation typically will range from 0 to about 3 double bonds peralkyl chain. The ratio of cis to trans unsaturated bond configurationscan range from about 1:100 to about 100:1. Other suitable examples foruse with polypropylene and/or polyethylene, a triglyceride whichcontains either stearic acid or palmic acid or both as the fatty acidcomponents, or a mixture of such triglycerides. Other suitablehydrophobizing melt additives may comprise erucamide or polysiloxanes.

As noted herein, in some examples, it may be desired that constituentsof the web material include filaments having surface energy propertiesthat make them hydrophilic. As noted, it may be desired in somecircumstances that filaments forming and proximate to theabsorbent-facing surface of the topsheet have hydrophilic surfaces. Insome examples this may be accomplished via use of hydrophilizing meltadditives to the resin(s) from which filaments are spun.

Any suitable hydrophilizing additive can be used. Some suitable examplesinclude those available from Techmer PM, Clinton, Tenn. sold under thetrade name of TECHMER PPM15560; TPM12713, PPM19913, PPM 19441, PPM19914,PPM112221 (for polypropylene), PM19668, PM112222 (for polyethylene).Additional examples are available from Polyvel Inc. located inHammonton, N.J., sold under the trade name of POLYVEL VW351 PP WettingAgent (for polypropylene); from Goulston Technologies Inc. located inMonroe, N.C. sold under the trade name HYDROSORB 1001; as well as thosehydrophilizing additives disclosed in U.S. Patent ApplicationPublication No. 2012/0077886 and U.S. Pat. Nos. 5,969,026 and 4,578,414.

Nucleating agents may be included along with melt additives. Nucleatingagents can help to drive more or faster blooming of either ahydrophilizing or hydrophobizing melt additive. A nucleating agent whenmelt-blended with constituent resin(s) and a hydrophilizing orhydrophobizing melt additive will enhance the hydrophilizing orhydrophobizing effect or wetting contact angle effect in the filaments(depending on the type of additive), as compared with the samehydrophilizing or hydrophobizing melt-additive used without a nucleatingagent. Suitable nucleating agents may include a nonitol, a trisamideand/or a sorbitol-based nucleating agent. Specific but non-limitingexamples include: organic nucleation agents such as MILLAD NX 8000 or(in its new trade name) NX ULTRACLEAR GP110B from Milliken & Company,Spartanburg, S.C. An example of an effective inorganic nucleating agentis CaCO₃, or other and especially nano-clay or nano-scale mineralmolecules.

Some melt additives may serve to enhance tactile softness and/or reducesurface coefficient of friction, as well as modify surface energy, andthereby serve dual purposes. For example, fatty amides when used as meltadditives may serve to both reduce surface friction, and enhancehydrophobicity of the filaments. These melt additives are listed hereinunder hydrophobic melt additives. Other non-limiting examples ofpotentially suitable softness-enhancing and hydrophobizing meltadditives are identified in US 2017/0258651.

During manufacture or in a post-treatment or even in both, the formednonwoven web materials contemplated herein may be treated withsurfactants or other agents to either hydrophilize the material or makeit hydrophobic. This is known in the fields of manufacturing andconverting nonwoven web materials used to make components of absorbentarticles. For example, a formed nonwoven web material used for atopsheet may be treated with a surfactant or other hydrophilizing agentso as to make it more receptive and/or permeable by aqueous bodyexudates such as urine. For other absorbent articles, the topsheet mayallowed to remain at its naturally hydrophobic state or be made evenmore hydrophobic, through the addition of a hydrophobizing material orsurfactant.

Spinning

As the polymer streams 122 a exit the spinnerets, a stream of quenchingair from the quench blower 550 at least partially quenches the polymersforming the streams, and, for certain polymers, induces crystallizationin the polymers. To increase the rate of crystallization/solidificationif desired, the quench blower(s) may be configured to direct quench airin a direction approximately perpendicular to the length of the streams.The quenching air may be cooled or heated as deemed suitable to be at atemperature of about 0 deg. C. to about 35 deg. C. and a velocity fromabout 100 to about 400 feet per minute when it contacts the polymerstreams. The streams may be quenched sufficiently to reduce theirsurface tackiness so as to prevent them from bonding or fusing togetherto any undesirable extent, upon contact therebetween, as they travel toand are deposited and accumulate on the forming belt 260.

After quenching, the polymer streams 122 a may be drawn into thevertical passage of an attenuator 552 and entrained by downward air flowgenerated by the attenuator 552. The attenuator may in some examples bepositioned 30 to 60 inches below the bottom of the spinnerets. The airflow generated by the attenuator moves at a higher downward velocitythan that of the entering quenched polymer streams. The attenuating airflow entrains the polymer streams and draws them downwardly, and therebyelongates and reduces their cross sections, thereby forming filaments122.

The filaments 122 exit the attenuator 552 and travel downwardlysubstantially in a z-direction with respect to the cycling forming belt260 having an upward-facing portion moving along the machine directionMD through the working location 561, beneath the attenuator 552. Theentraining air exiting the attenuator may be drawn through theair-permeable portions of the forming belt 260 by the forming vacuumsystem 555, and the filaments 122 are stopped in their z-directiontravel by the outer receiving side 260 a of the forming belt 260, aredeposited and accumulated thereon, and then travel with the forming belt260 in the machine direction along therewith. It will be appreciatedthat the rate of deposit and accumulation of the filaments on theforming belt 260 may be controlled by controlling the speed at which theforming belt is cycled, the rate at which the filaments are spun, or acombination of these. As will be further explained below, the formingbelt 260 may be configured with features that affect localized rates anddepths of accumulation of filaments across its overall surface area inthe x-y plane, to result in formation of a batt of filaments 270 andsubsequent finished nonwoven web material 280 with a desired orderedarrangement of regions of varying basis weight and/or filament areadensity and/or thickness or caliper.

In some circumstances it may be desired to include discrete filaments ofdiffering compositions in the nonwoven web material. It will beappreciated that this may be accomplished by configuring equipmentcarrying differing polymer resins arranged in parallel or inseries/sequentially to one or more combinations of spin pack(s),quenching equipment and attenuating equipment configured to spinfilaments and direct them at the forming belt. In one non-limitingexample, it may be desired that the nonwoven web material have layereddeposits of filaments of differing compositions with differing levels ofhydrophilicity/hydrophobicity. Referring to FIG. 21, in a particularexample, it may be desired that hydrophobic filaments are predominatelypresent proximate the wearer-facing surface 124 of a topsheet material,while hydrophilic filaments are predominately present proximate theabsorbent-facing surface 123. It will be appreciated that, to producesuch a configuration, the filament spinning equipment may be configuredto spin and deposit a first layer 280 a of hydrophobic filaments ontothe forming belt, and sequentially downstream in the process, to spinand deposit a second layer 281 of differing, hydrophilic filaments overthe hydrophobic filaments, as the batt moves along a machine directionon the moving forming belt.

Compaction and Bonding

The process line 500 may further include one or more consolidatingdevices such as compaction rolls 570 and 572, which form a nip 570 athrough which the batt 270 may be compacted. Optionally, one or bothcompaction rolls 570, 572 may be heated to promote partial softening andplastic deformation of the filaments. It may be desired, further, toapply a combination of heat and pressure to the filaments in the nip 570a sufficient to induce some bonding between intermeshing/crossingfilaments traveling through nip 570 a.

Compaction facilitates neat removal of the batt 270 from the formingbelt, and some bonding may enhance this effect as well as impart addedmachine- and/or cross-direction tensile strength to the finishedmaterial. The compaction rolls 570, 572 may be a pair of smooth surfacestainless steel rolls with independent heating controllers. One or bothcompaction rolls may be heated by electric elements or hot oilcirculation. The gap between the compaction rolls may be controlled,e.g., hydraulically, to impose desired pressure on the batt as it passesthrough the nip 570 a. In one example, with a forming belt caliper of1.4 mm, and a spunbond nonwoven having a basis weight of 30 gsm, the nipgap between the compaction rolls 570, 572 may be about 1.35 to 1.50 mm.

In one example, upper compaction roll 570 may be heated to a temperaturesufficient to induce melting of bond filaments on the upper surface ofthe batt 270, to impart cohesion and strength to the batt that mayfacilitate its removal from forming belt 260 without losing integrity.As shown in FIG. 11, for example, as rolls 570 and 572 rotate, formingbelt 260 with the batt laid down on it enter the nip 570 a between rolls570 and 572. Heated roll 570 can heat the portions of nonwoven fabric 10that are pressed against it most closely, by land surfaces 262 a ofairflow blocking structures 262 on forming belt 260 (described below),to deform and/or flatten and/or bond filaments proximate the uppersurface (i.e., attenuator-side) surface of batt 270, to an extentdesired. As can be understood by the description herein, the attenuatedregions in which filaments are so deformed will reflect the pattern ofthe airflow blocking structures 262 on forming belt 260.

After compaction, the compacted batt may be lifted away or separatedfrom the forming belt 260 and be directed through a second nip 571 aformed by calender rolls 571, 573. The calender rolls 571, 573 may bestainless steel rolls, one having an engraved or otherwise formedpattern of raised bonding protrusions about its cylindrical surface(bonding roller), and the other being a smooth roll (anvil roller). Thebonding roller, or both bonding and anvil rollers, may be heated suchthat they heat and partially melt the filaments so as to cause them tofuse together in the nip, between the radially outermost surfaces of thebonding protrusions and the anvil roller. The bonding protrusions on thebonding roller may be configured in any suitable regular pattern ofrelatively closely-spaced bonding “pins” that will effect a like patternof point bonds in the finished web material 280. The radially outermostsurfaces of the bonding protrusions effect localized elevatedcompression of the batt in the nip 571 a, between the bondingprotrusions and the anvil roller. These surfaces may have a cumulativesurface area about the bonding roller that amounts to a percent fractionof the total cylindrical surface area of the working portion of thebonding roller (bonding area percentage), which will be approximatelyreflected in the percent fraction of the surface area, in the x-y plane,of the web material that is bonded (bonded area percentage). The bondingarea percentage of the bonding roller, and the resulting bonded areapercentage of the web material, may be approximately from 3% to 30%,from 6% to 20%, or from 7% to 15%. A pattern of thermal calenderpoint-bonds may serve to improve cohesiveness of the web, and enhancemachine direction and cross-direction tensile strength and dimensionalstability, useful in downstream processing and incorporation of theformed nonwoven web material into finished products.

Additionally or alternatively, in some examples the batt may be bondedvia a hot air bonding process. Through-air thermal bonding may beanother approach to create higher loft nonwoven structures which may bedesired in some circumstances. Through-air thermal bonding involves theapplication of hot air to the surface of the filament batt. The hot airflows through holes in a plenum positioned just above the nonwoven.However, the air is not pushed through the nonwoven, as in common hotair ovens. Negative pressure or suction pulls the air through the openconveyor apron that supports the nonwoven as it passes thorough theoven. Pulling the air through the nonwoven fabric allows much more rapidand even transmission of heat and minimizes fabric distortion. As analternative to use of a conventional through-air bonding unit, it iscontemplated placing the bonding unit over the forming belt 260 while avacuum is operated beneath the belt to draw hot air through the batt,effecting a process similar to that effected by a conventionalthrough-air bonding unit.

Forming Belt Manufacture

A forming belt 260 may be made according to the methods and processesdescribed in U.S. Pat. Nos. 6,610,173; 5,514,523; 6,398,910; or US2013/0199741, each with the improved features and patterns disclosedherein for making spunbond nonwoven webs. The '173, '523, '910 and '741disclosures describe belts that are representative of papermaking beltsmade with cured resin on a belt substrate member, which belts, withimprovements and suitable configurations, may be utilized as describedherein.

A forming belt 260 having three-dimensional features and patterns formaking spunbond nonwoven webs may also be made by the following methodsand processes and/or on the following apparatuses, including withmodifications as desired for structures taught herein: rotary screenprocesses as taught in U.S. Pat. No. 7,799,382; polymer extrusion astaught in US 2007/0170610; resin system grafting as taught in U.S. Pat.No. 7,105,465; perforated film as taught in U.S. Pat. No. 8,815,057;successive layer treatment as taught in US 2006/0019567; polymericdroplet deposition as taught in U.S. Pat. No. 7,005,044; polymericdroplet deposition with a sacrificial material as taught in U.S. Pat.No. 7,014,735; air permeable film technology as taught by U.S. Pat. No.8,454,800 or 8,822,009; multilayer belt structures as taught in US2016/0090692; laser etching as taught by U.S. Pat. No. 8,758,569 or8,366,878; extruded mesh technology as taught in US 2014/0272269;nonwoven belts as described in US 2008/0199655; and additivemanufacturing methods and processes as taught in US 2015/0102526A1, orUS 2016/0159007, or WO 2016/085704, or US 2016/0185041.

An example of a forming belt 260 of the type useful for purposes of thepresent disclosure and which may be made according to the disclosure ofU.S. Pat. No. 5,514,523, is schematically depicted in FIGS. 12-14. Astaught in the '523 patent, a flat sheet of substrate belt material 261is thoroughly coated with a liquid photosensitive polymeric resin to apreselected thickness. The substrate belt material 261 (called a“reinforcing structure” in the '523 patent) may be an air-permeable wiremesh or screen material, a woven mat or sheet material, an aperturedmetal or polymer sheet material, or any other material that providessuitable process dimensional stability and durability under conditionsof use contemplated herein, and a relatively high degree of airpermeability in a z-direction combined with a relatively small spacingand sizing of air passageways, such that spun filaments striking thebelt will accumulate thereon rather than being blown or drawn throughair passageways to any substantial extent, by air moving therethrough inthe z-direction. A transparent film or mask printed with, or otherwisereflecting in the negative, opaque portions having defining a desiredpattern, arrangement, sizes and shape(s) for desired airflow blockingstructures 262, is laid down over the liquid photosensitive resin. Theresin is then exposed to light of an appropriate wavelength through thefilm, such as UV light for a UV-curable resin. This exposure to lightcauses curing of the resin beneath the transparent portions (e.g.,non-printed portions) of the mask. Uncured resin (beneath the opaqueportions in the mask) may then be removed from the substrate (e.g., viause of a solvent), leaving behind solid, airflow blocking structuresformed of the cured resin formed on the substrate, arranged in thedesired pattern and shape(s), for example, the pattern of airflowblocking structures 262 shown in FIG. 12. Other patterns of airflowblocking structures for imparting any desired decorative or functionalfeatures to a nonwoven web material can also be formed. Airflow blockingstructures 262 form and define airflow blocked regions 264 of formingbelt 260, through which z-direction air flow through the belt isblocked. The portions of the substrate belt material 261 on which theresin was left uncured, and from which it was removed, form and defineairflow permeable regions 263 of forming belt 260, through whichz-direction air flow through the belt is permitted. The resin may beformed and cured on the belt to a depth and in a manner such thatairflow blocking structures 262 have a desired z-direction depth, andflat land surfaces 262 a generally along an x-y plane. Followingformation of the airflow blocking structures, ends of the sheet ofsubstrate belt material with the airflow blocking structures formedthereon may be joined in any suitable manner to form a continuousforming belt 260.

Batt and Web Formation

FIGS. 15-17 illustrate the manner in which spun filaments may beaccumulated on forming belt 260, with the location and depth of filamentaccumulation being affected by the arrangement and depth of airflowblocking structures 262 on the forming belt. Because the filaments areentrained in attenuating air being driven downward and drawn through thebelt in the z-direction by the forming vacuum system 555 (see FIG. 11)they follow the air as it finds its way around and past the blockingstructures 262 and are deposited predominately on/over airflow permeableregions 263 of the forming belt. Accordingly, the filaments accumulateto a greater depth and/or filament area density and weight over theairflow permeable regions 263, to form built-up regions 166 of a batt270 of filaments accumulated on the belt. As previously noted, theextent of filament accumulation on the forming belt, generally, may becontrolled by controlling the belt cycling speed and the filamentspinning rate, or a combination thereof. Turbulence and resultingrandomness in the air flow as it approaches the belt, and machinedirection movement of the belt, will cause a smaller accumulation offilaments (which are generally continuous as spun) crossing over andthereby accumulating to a lesser extent over the land surfaces 262 a ofthe airflow blocking structures 262, forming attenuated regions 163 inthe batt 270 of accumulated filaments. This effect is schematicallyillustrated in FIG. 9, which depicts a relatively small accumulation offilaments 122 crossing through channel portions 164, as they may beformed by appropriately configured airflow blocking structures, and alsoin FIG. 16. The relative distribution of filaments between attenuatedregions 163 and built-up regions 166, and resulting relative basisweights therebetween, may be adjusted at least in part by regulating theair flow rate drawn through the forming belt 260 by the forming vacuumsystem 555. Generally, a relatively lesser number of filaments willaccumulate over the land surfaces 262 a of the airflow blockingstructures 262, and a relatively greater number of filaments willaccumulate over the airflow permeable regions 263, with a relativelygreater air flow rate into vacuum system 555—and vice versa.Alternatively or in combination with regulation of air flow rate drawnby the forming vacuum system 555, the relative distribution of filamentsbetween the attenuated regions 163 and the built-up regions 166 may becontrolled by selection of the substrate forming belt material 261.Generally, a relatively lesser number of filaments will accumulate overthe land surfaces 262 a of the airflow blocking structures 262, and arelatively greater number of filaments will accumulate over the airflowpermeable regions 263, with a relatively greater air permeability of thesubstrate belt material 261 and consequently, of the airflow permeableregions 263, of the forming belt 260—and vice versa.

Following compaction between compaction rollers 571, 572 (shown in FIG.11) and subsequent removal from the forming belt, as illustrated in FIG.17 the batt 270 will have a structure with built-up regions 166 andattenuated regions 163 substantially corresponding to the arrangement ofairflow blocking structures on the forming belt. As noted, filamentsand/or portions thereof occupying the attenuated regions 163 may besomewhat plastically deformed (e.g., flattened) as a result ofcompaction between compaction roller 570 and the land surfaces 262 a ofthe airflow blocking structures 262. Correspondingly, filaments and/orportions thereof occupying the built-up regions 166 generally will notbe deformed by compaction or may be deformed to a substantially lesserextent, because during compaction they are disposed in the spacesbetween the airflow blocking structures and thus are not so closelycompressed as the batt passes through compaction nip 270 a.

Using a forming belt 260 and process as described above, a differencebetween the fiber and/or filament area density, and/or the basis weight,of the batt, of the built-up regions versus the attenuated regions canbe achieved to a level of 2:1, 3:1 or even 4:1 or greater.

From the description above and the figures, it will also be appreciatedthat a formed nonwoven web material manufactured according to theprocess described will exhibit “sidedness,” meaning a difference betweenfeatures of the surface that will be comprised by a wearer-facingsurface of a topsheet, and features of the opposing surface that will becomprised by an absorbent-facing surface of the topsheet. Referring toFIGS. 16 and 17, for example, it will be appreciated that the surface ofthe batt (and subsequent nonwoven web material) formed by filaments thatreached the forming belt first in time (first-formed surface) willexhibit topographic features and/or texture, according to the orderedarrangement, that have substantially greater z-direction depth, than anytopographic features and/or texture of the opposing surface, i.e., thesurface formed by filaments that reached the forming belt last in time(last-formed surface), prior to compaction of the batt. As a result ofsuch sidedness, visual discernibility of zones reflecting an orderedarrangement may be substantially greater on the first-formed surface(which may form the wearer-facing surface of a topsheet). Consequently,the visual impact of the zones and of the resulting topographic/texturalfeatures may be more dramatic on the first-formed surface, than on theopposing last-formed surface. In conjunction therewith and with themethod of manufacture, those portions of filaments occupying theattenuated regions will generally be closer in the z-direction, to thelast-formed surface.

Although a melt spinning/spunbond process and deposition of filamentsonto a forming belt is described above, it is also contemplated thatother filaments and/or fiber deposition and basis weight distributiontechniques and processes may be employed, including so-called co-formingprocesses described in, for example, U.S. Pat. Nos. 9,944,047;8,017,534; 5,508,102; 4,100,324; and US 2003/0211802; PCT applicationpublication number WO 2018/064595 A1; and US 2018/002848; US2017/002486; US 2017/000695; US 2017/0342617; US 2016/0355950; and othertechniques such as spunlace formation techniques in which a web formedof airlaid fibers (including natural and/or synthetic/polymeric fibers)have fiber location and distribution within the web material modified bycontrolled and ordered hydroenhancement/hydroentanglement, to form theordered arrangement of channel portions, hinge portions, built-up andattenuated regions contemplated herein, and resulting orderedarrangements of features, which may be formed so as to be visuallydiscernible.

Balancing Filament Surface Hydrophobicity and Hydrophilicity

As discussed above, filaments to be spun and accumulated to form thenonwoven web may be extruded from a polymer resin or blend of resinsselected for various properties they impart to the filaments includingtensile strength, tactile softness (affected by properties such asfilament stiffness and surface coefficient of friction),hydrophilicity/hydrophobicity, etc., as well as cost. Additionally, thefilaments and/or the formed nonwoven web may receive post-formationtreatments applied, such as, for example, application of a surfactant toone or more surfaces.

Depending on the polymeric resin(s) used to spin them, surfaces ofindividual synthetic fibers or filaments may be slightly to highlyhydrophilic, slightly to highly hydrophobic, or neutral, affecting theextent of the fibers'/filaments' tendency, or lack thereof, to attractaqueous fluid and draw it along their surfaces. Within a nonwoven webstructure that includes numerous fiber/filament surfaces of varyinggeometry and/or spatial orientation, the extent of hydrophilicity orhydrophobicity of individual fiber surfaces in the aggregate, togetherwith the extent of fiber consolidation that affects the porosity of thestructure, will on a macroscopic level impart overall hydrophilicity,hydrophobicity, wicking, and absorption properties to the web structure.Including fibers or filaments of differing composition in the nonwovenwill also have impact.

Thus, depending upon the type(s) of constituent fibers or filaments usedto form it, the macroscopic surface of a nonwoven web may be neutral,slightly to highly hydrophilic or slightly to highly hydrophobic,affecting the extent of its tendency to attract aqueous fluid, conduct(“wick”) the fluid through interstices or pores within the fibrousstructure, and retain (i.e., absorb) the fluid within the structure.

The extent to which a nonwoven as an overall structure tends to repel,or alternatively to attract, wick and/or retain aqueous fluid may bemanipulated through selection of fiber/filament material composition,fiber spinning/processing, web structuring and fiber consolidation, andpost formation treatment. Additives may be blended with polymer resins,which will modify the extent of hydrophilicity or hydrophobicity of thesurfaces of the fibers or filaments spun from the resins. Followingspinning of the fibers or filaments and/or formation of the nonwoven webmaterial, hydrophobizing or hydrophilizing agents may be applied to thesurfaces of the fibers or filaments and/or nonwoven.

In designing a nonwoven suitable for use as topsheet material for awearable absorbent article such as a feminine hygiene pad, themanufacturer may face an inherent conflict. On one hand, the materialmust be sufficiently hydrophilic and have suitable porosity to accept adischarge of fluid such as urine or menses, and wick it in thez-direction so as to pass it through to an absorbent structure disposedbeneath the topsheet. A topsheet that does not sufficiently and rapidlyaccept discharged fluid and move it in the z-direction down to theabsorbent structure beneath increases the risk that the fluid willescape the article and soil underwear, outer garments, bedclothes, etc.On the other hand, if the material is hydrophilic and has a porositylevel conducive to effective wicking, it may also be prone to incompletedrainage and/or rewetting, i.e., retaining and holding some portion ofthe discharged fluid, or reacquiring fluid from the absorbent structure.A topsheet that retains discharged fluid or is prone to rewetting isgenerally not preferred by users/wearers because it tends to feelunpleasantly wet and can promote overhydration of the skin.

It has been learned that a balance of hydrophobic and hydrophilicfilament/nonwoven properties may be achieved within the structuredtopsheet material described herein, between suitable fluid acquisitionrate and suitable low rewet tendency. Through prototyping and consumertesting it has been learned that consumer-users of feminine hygienepads, for example, most prefer a pad configured with a topsheet thatexhibits a maximum Rewet (expressed in grams of fluid) of no greaterthan 0.50 g, more preferably no greater than 0.45 g., and even morepreferably no greater than 0.40 g, when the pad is tested using theRewet measurement method set forth herein. Rewet as measured forpurposes herein is a reflection of the absorbent structure/topsheetcombination's tendency (or lack thereof) to pass absorbed fluid backinto the topsheet under particular conditions, which reflect thetopsheet's tendency to undesirably feel wet to the user under useconditions. Using the materials and topsheet structuring methodsdescribed herein, for example, a combination of polymeric spinning resin(e.g., polyolefin, e.g., polypropylene and/or polyethylene) whoseinherent hydrophobicity may be supplemented by inclusion of a suitablehydrophobizing melt additive, rewet tendencies can be reduced, even downto substantially little or no rewet tendency.

However, a topsheet formed of a nonwoven of spun filaments with very lowrewet tendency will necessarily be quite hydrophobic and/or of lowporosity—and therefore, resistant to fluid penetration and movement inthe z-direction therethrough. Upon contacting the wearer-facing surfaceof such a topsheet, fluid will tend to roll over the surface along anx-y direction without penetrating it, increasing the risk that the fluidwill remain in contact with the user's skin and create an insecure wetfeeling, and the risk that it will escape the pad and soil surroundingunderwear, outer garments, etc. Accordingly, while a low rewet tendencyfor a topsheet may be desirable in theory, it must be balanced withother features that enable the topsheet to receive and move the fluid ina z-direction.

An ordered arrangement of zones including attenuated regions andbuilt-up regions as described herein, which may be combined withapplication of a surfactant as described herein, provides a way ofstriking this balance. The attenuated regions, being relatively sparselypopulated by filaments, provide pathways for fluid to move in az-direction through the topsheet. Additionally, application of asurfactant to the absorbent-facing side of the topsheet web (where theabsorbent-facing side is the side of the web that faced away from theforming belt 260 during formation of the web) results in a predominantnumber of filaments in the attenuated regions having surfactant on theirsurfaces and thereby being rendered hydrophilic, while filaments on thewearer-facing side of the built-up regions 166 remain relativelyhydrophobic. On a macroscopic level, the attenuated regions exhibitbehavior akin to small drains in the topsheet through which fluid willbe drawn in a z-direction down through the topsheet. The surfactant maybe selected and applied at a chosen coverage quantity to adjust therapidity with which fluid will move through the topsheet.

However, just as excessive hydrophobicity can frustrate fluid acceptanceand movement within the topsheet, excessive hydrophilicity imparted by,e.g., excessive application of surfactant, can impart unacceptable rewettendency. Through prototyping and consumer testing it has been learnedthat consumer-users of feminine hygiene pads most prefer a padconfigured with an absorbent structure and a topsheet that exhibits anAcquisition Time (expressed in seconds) of no greater than 25 s, whenthe pad is tested using the Acquisition Time measurement method setforth herein. Acquisition Time as measured for purposes herein is areflection of the absorbent structure/topsheet combination's tendency(or lack thereof) to receive and transfer fluid in a z-direction to theabsorbent structure under particular conditions. Rapid acquisition ispreferable, but cannot be reduced freely without adversely increasingrewet tendency of the topsheet. Using the materials and topsheetstructuring methods described herein, for example, a combination offibers having inherent and/or supplemented hydrophobicity, AcquisitionTime can be reduced. It has been learned that consumer users most prefera combination of absorbent structure and topsheet in which a balance hasbeen struck between an Acquisition Time no greater than 25 s, morepreferably no greater than 20 s, and even more preferably no greaterthat 15 s and Rewet no greater than 0.50 g.

Data collected through experimentation and consumer testing suggeststhat lower limits on these ranges may exist, within the context of thematerials and structures described herein. Through experimentation thelowest Rewet level achieved with an Acquisition Time no greater than 15s was about 0.24 g. The lowest Acquisition Time with a Rewet no greaterthan 0.50 g was about 4 s. Without intending to be bound by theory,however, it is believed that these combined values may be reducedfurther with suitable experimentation with materials and structures asdescribed herein. The operative combination of maximum Rewet and maximumAcquisition Time is believed to be an important discovery of consumerpreference for and consumer satisfaction with a pad with a functionallystructured, visually appealing topsheet as described herein.

EXPERIMENTAL EXAMPLES

Prototype/sample feminine hygiene pads were manufactured having thefollowing components:

Each pad had a topsheet cut from a nonwoven web material formed ofside-by-side bicomponent spunbond filaments with a 70:30 componentweight ratio of two differing polypropylene resin compositions.Approximately 1 percent by weight titanium dioxide was blended into theresin compositions. Erucamide was added to the resin compositions forthe differing samples, in quantities shown in Table 1 below. Thediffering polypropylene components exhibited differing contraction rateson cooling, resulted in helically crimped or curled spun filaments.Spinning and attenuating equipment was adjusted to impart the spunfilaments with an average diameter of approximately 18 μm. The spunfilaments were deposited onto a moving forming belt formed with airflowblocking structures of shapes and sizes reflected by the image of themask depicted in FIG. 28, to result in a nonwoven having the orderedarrangement of zones depicted in FIG. 26B. Filament spinning anddeposition rates were controlled to impart the nonwoven with an averagebasis weight of approximately 32 gsm. Following filament spinning anddeposition on the forming belt, the batt was compacted in a nip asschematically depicted as element 570 a in FIG. 11, wherein thecompaction roller was heated to approximately 140 C. Followingcompaction and removal from the forming belt the batt was calenderbonded in a nip between patterned and anvil bonding rollers heated toapproximately 140-145 C. The patterned bonding roller was configured toimpart a regular pattern of regularly-spaced circular bonds each havinga diameter of approximately 0.8 mm, and suitable numerical density perunit surface area to result in a total bonded area for the finished webproduct of approximately 10 percent of the total surface area on oneside.

The topsheet was overlaid directly onto a secondarytopsheet/acquisition/distribution layer having a basis weight of 55 gsmand formed of carded spunlace staple fibers consisting of a blend of 40percent by weight viscose fibers of 1.7 decitex, 40 percent by weightpolyethylene/polypropylene bicomponent fibers of 1.7 decitex, and 20percent by weight PET fibers of 4.4 decitex.

The secondary topsheet directly overlaid an additional absorbentstructure layer formed of an blend of cellulose fibers, bicomponentpolymer staple fibers and particles of absorbent gelling material,airlaid to a basis weight of 160 gsm, an absorbent structure compositionappearing in ALWAYS ULTRA feminine hygiene pads currently marketed byThe Procter & Gamble Company in Western Europe.

The additional absorbent structure layer directly overlaid a backsheetformed of liquid impervious polyethylene film, which was bonded aboutits perimeter via adhesive to the topsheet, whereby the topsheet and thebacksheet formed an envelope containing the absorbent structureincluding the secondary topsheet and the additional absorbent structurelayer.

For purposes of studying the effects and interactions between an exampleof a melt additive and an example of a surfactant and consumerpreferences, the polypropylene resins used to spin the topsheetfilaments, for varying sample, had varying levels of erucamide added andblended into the melted resin as melt additive prior to spinning. Thefinished topsheet materials for the varying samples had the indicatedvarying levels of surfactant applied to the outward/core-facing surface,via inkjet printing equipment. The surfactant applied was STANTEX S6887,obtained via a U.S. sales office representing Pulcra Chemicals/FashionChemicals GmbH & Co., Geretsried, Germany. The amount of melt additiveincluded and the amount of surfactant applied for various samples is setforth in Table 1 below.

For each sample, the Acquisition Time and the Rewet were measured usingthe Acquisition Time and Rewet Measurement methods set forth below. Fromthe data, it can be seen that Acquisition Time and Rewet in combinationmay be manipulated by manipulation of the amounts of melt additive addedand surfactant applied. As noted, it has been concluded from consumertesting that a pad having a combination of Rewet of no greater than 0.50g, more preferably no greater than 0.45 g, and even more preferably nogreater than 0.40 g, and an Acquisition Time of no greater than 25seconds, more preferably no greater than 20 seconds, and even morepreferably no greater than 15 seconds, is acceptable or preferred byconsumers, over a pad that falls outside these parameters. Generally,the data reflected that, while a relatively shorter Acquisition Time waspreferred, a trade-off was a relatively greater Rewet, which was notpreferred. Manipulation of features described herein, including atopsheet formed as described herein, enabled a suitable balance ofacceptable levels of these fluid handling characteristics.

TABLE 1 Consumer acceptable/ Melt Surfactant Acquisition preferredSample additive level Time Rewet (Yes or # % by weight (gsm) (seconds)(g) No) 17 0.0% 1.00 5.5 0.644 N 20 0.5% 1.00 5.5 0.556 N 16 0.0% 0.356.2 0.593 N 26 1.5% 0.85 6.2 0.416 Y  5A 1.5% 1.00 6.7 0.464 Y 19 0.5%0.35 7.2 0.463 Y 25 1.5% 0.30 8.3 0.364 Y 18 0.5% 0.15 8.7 0.386 Y  2A1.5% 0.35 8.8 0.424 Y 15 0.0% 0.15 9.0 0.548 N  1 1.5% 0.15 11.2 0.347 Y24 1.5% 0.13 13.7 0.288 Y 30 1.5% 0.10 25.5 0.269 N 31 1.5% 0.05 48.00.183 N

Test/Measurement Methods

Localized Basis Weight

Localized basis weight of a region of a formed nonwoven web material maybe determined by several available techniques, but a simplerepresentative technique when the region is suitably large involvescutting a sample piece of the web representing the selected region fromthe overall area of the material. The sample piece is then weighed anddivided by its area to yield the localized basis weight of the nonwovenfabric in, units of grams per square meter (gsm). Results are reportedas a mean of 2 samples per selected region.

Micro-CT Intensive Property Measurement Method

The micro-CT intensive property measurement method measures the basisweight, thickness and volumetric density values within visuallydiscernable regions of a sample of nonwoven web material. It is based onanalysis of a 3D x-ray sample image obtained on a micro-CT instrument (asuitable instrument is the Scanco μCT 50 available from Scanco MedicalAG, Switzerland, or equivalent). The micro-CT instrument is a cone beammicrotomograph with a shielded cabinet. A maintenance free x-ray tube isused as the source with an adjustable diameter focal spot. The x-raybeam passes through the sample, where some of the x-rays are attenuatedby the sample. The extent of attenuation correlates to the mass ofmaterial the x-rays have to pass through. The transmitted x-rayscontinue on to the digital detector array and generate a 2D projectionimage of the sample. A 3D image of the sample is generated by collectingseveral individual projection images of the sample as it is rotated,which are then reconstructed into a single 3D image. The instrument isinterfaced with a computer running software to control the imageacquisition and save the raw data. The 3D image is then analyzed usingimage analysis software (a suitable image analysis software is MATLABavailable from The Mathworks, Inc., Natick, Mass., or equivalent) tomeasure the basis weight, thickness and volumetric density intensiveproperties of regions within the sample.

Sample Preparation

To obtain a sample for measurement, lay a single layer of the formednonwoven web material of interest out flat on a work surface, and diecut therefrom a circular piece with a diameter of 30 mm.

If the material is a layer of an absorbent article, for example atopsheet, backsheet nonwoven, acquisition layer, distribution layer, orother component layer; tape the absorbent article to a rigid flatsurface in a planar configuration. Carefully separate the layer from theabsorbent article. A scalpel and/or cryogenic spray (to substantiallydeactivate adhesives) (such as Cyto-Freeze, Control Company, HoustonTex.) may be used as necessary to remove a substrate layer fromadditional underlying layers, if necessary, to avoid any longitudinaland lateral extension of the material. Once the substrate layer has beenremoved from the article proceed with die cutting the sample asdescribed above.

A sample may be cut from any location containing the zone to beanalyzed. Within a zone, regions to be analyzed are ones associated withan ordered arrangement as defined herein. The zone includes a least tworegions. A zone and regions thereof may be visually discernible orotherwise identifiable due to changes in fiber and/or filament areadensity, basis weight, opacity, caliper/thickness or z-directionelevation. Regions within different samples taken from the samesubstrate material may be analyzed and compared to each other. Careshould be taken to avoid folds, wrinkles or tears when selecting alocation on the formed nonwoven web material of interest for sampling.

Image Acquisition

Set up and calibrate the micro-CT instrument according to themanufacturer's specifications. Place the sample into the appropriateholder, between two rings of low density material, which have an innerdiameter of 25 mm. This will allow the central portion of the sample tolay horizontal and be scanned without having any other materialsdirectly adjacent to its upper and lower surfaces. Measurements shouldbe taken in this region. The 3D image field of view is approximately 35mm on each side in the x-y plane with a resolution of approximately 5000by 5000 pixels, and with a sufficient number of 7 micron thick slicescollected to fully include the z-direction of the sample. Thereconstructed 3D image resolution contains isotropic voxels of 7microns. Images are acquired with the source at 45 kVp and 133 pA withno additional low energy filter. These current and voltage settings maybe optimized to produce the maximum contrast in the projection data withsufficient x-ray penetration through the sample, but once optimized heldconstant for all substantially similar samples. A total of 1500projections images are obtained with an integration time of 1000 ms and3 averages. The projection images are reconstructed into the 3D image,and saved in 16-bit RAW format to preserve the full detector outputsignal for analysis.

Image Processing

Load the 3D image into the image analysis software. Threshold the 3Dimage at a value which separates, and removes, the background signal dueto air, but maintains the signal from the sample fibers within thesubstrate.

Three 2D intensive property images are generated from the threshold 3Dimage. The first is the Basis Weight Image. To generate this image, thevalue for each voxel in an x-y plane slice is summed with all of itscorresponding voxel values in the other z-direction slices containingsignal from the sample. This creates a 2D image where each pixel now hasa value equal to the cumulative signal through the entire sample.

In order to convert the raw data values in the Basis Weight Image intoreal values a basis weight calibration curve is generated. Obtain asubstrate that is of substantially similar composition as the samplebeing analyzed and has a uniform basis weight. Follow the proceduresdescribed above to obtain at least ten replicate samples of thecalibration curve substrate. Accurately measure the basis weight, bytaking the mass to the nearest 0.0001 g and dividing by the sample areaand converting to grams per square meter (gsm), of each of the singlelayer calibration samples and calculate the average to the nearest 0.01gsm. Following the procedures described above, acquire a micro-CT imageof a single layer of the calibration sample substrate. Following theprocedure described above, process the micro-CT image, and generate aBasis Weight Image containing raw data values. The real basis weightvalue for this sample is the average basis weight value measured on thecalibration samples. Next, stack two layers of the calibration substratesamples on top of each other, and acquire a micro-CT image of the twolayers of calibration substrate. Generate a basis weight raw data imageof both layers together, whose real basis weight value is equal to twicethe average basis weight value measured on the calibration samples.Repeat this procedure of stacking single layers of the calibrationsubstrate, acquiring a micro-CT image of all of the layers, generating araw data basis weight image of all of the layers, the real basis weightvalue of which is equal to the number of layers times the average basisweight value measured on the calibration samples. A total of at leastfour different basis weight calibration images are obtained. The basisweight values of the calibration samples must include values above andbelow the basis weight values of the original sample being analyzed toensure an accurate calibration. The calibration curve is generated byperforming a linear regression on the raw data versus the real basisweight values for the four calibration samples. This linear regressionmust have an R2 value of at least 0.95, if not repeat the entirecalibration procedure. This calibration curve is now used to convert theraw data values into real basis weights.

The second intensive property 2D image is the Thickness Image. Togenerate this image the upper and lower surfaces of the sample areidentified, and the distance between these surfaces is calculated givingthe sample thickness. The upper surface of the sample is identified bystarting at the uppermost z-direction slice and evaluating each slicegoing through the sample to locate the z-direction voxel for all pixelpositions in the x-y plane where sample signal was first detected. Thesame procedure is followed for identifying the lower surface of thesample, except the z-direction voxels located are all the positions inthe x-y plane where sample signal was last detected. Once the upper andlower surfaces have been identified they are smoothed with a 15×15median filter to remove signal from stray fibers. The 2D Thickness Imageis then generated by counting the number of voxels that exist betweenthe upper and lower surfaces for each of the pixel positions in the x-yplane. This raw thickness value is then converted to actual distance, inmicrons, by multiplying the voxel count by the 7 μm slice thicknessresolution.

The third intensive property 2D image is the Volumetric Density Image.To generate this image divide each x-y plane pixel value in the BasisWeight Image, in units of gsm, by the corresponding pixel in theThickness Image, in units of microns. The units of the VolumetricDensity Image are grams per cubic centimeter (g/cc).

Micro-CT Basis Weight, Thickness and Volumetric Density IntensiveProperties

Begin by identifying the region to be analyzed. A region to be analyzedis one associated with a zone. The zone includes a least two regions. Azone and regions thereof, may be visually discernible or otherwiseidentifiable due to changes in fiber and/or filament area density, basisweight, opacity, caliper/thickness or z-direction elevation. Next,identify the boundary of the region to be analyzed. The boundary of aregion is identified by visual discernment of differences in intensiveproperties when compared to other regions within the sample. Forexample, a region boundary may be identified based by visuallydiscerning a thickness/caliper difference when compared to anotherregion in the sample. Any of the intensive properties may be used todiscern region boundaries on either the physical sample itself of any ofthe micro-CT intensive property images. Once the boundary of the regionhas been identified, draw an oval or circular “region of interest” (ROI)within the interior of the region. The ROI should have an area of atleast 0.1 mm², and be selected to measure an area with intensiveproperty values representative of the identified region. From each ofthe three intensive property images calculate the average basis weight,thickness and volumetric density within the ROI. Record these values asthe region's basis weight to the nearest 0.01 gsm, thickness to thenearest 0.1 micron and volumetric density to the nearest 0.0001 g/cc.

Acquisition Time and Rewet Measurement

Artificial Menstrual Fluid (AMF) Preparation

The Artificial Menstrual Fluid (AMF) is composed of a mixture ofdefibrinated sheep blood, a phosphate buffered saline solution and amucous component. The AMF is prepared such that it has a viscositybetween 7.15 to 8.65 centistokes at 23° C.

Viscosity on the AMF is performed using a low viscosity rotaryviscometer (a suitable instrument is the Cannon LV-2020 RotaryViscometer with UL adapter, Cannon Instrument Co., State College, Pa.,or equivalent). The appropriate size spindle for the viscosity range isselected, and instrument is operated and calibrated as per themanufacturer. Measurements are taken at 23° C.±1 C.° and at 60 rpm.Results are reported to the nearest 0.01 centistokes.

Reagents needed for the AMF preparation include: defibrinated sheepblood with a packed cell volume of 38% or greater (collected understerile conditions, available from Cleveland Scientific, Inc., Bath,Ohio, or equivalent), gastric mucin with a viscosity target of 3-4centistokes when prepared as a 2% aqueous solution (crude form,available from Sterilized American Laboratories, Inc., Omaha, Nebr., orequivalent), 10% v/v lactic acid aqueous solution, 10% w/v potassiumhydroxide aqueous solution, sodium phosphate dibasic anhydrous (reagentgrade), sodium chloride (reagent grade), sodium phosphate monobasicmonohydrate (reagent grade) and distilled water, each available from VWRInternational or an equivalent source.

The phosphate buffered saline solution consists of two individuallyprepared solutions (Solution A and Solution B). To prepare 1 L ofSolution A, add 1.38±0.005 g of sodium phosphate monobasic monohydrateand 8.50±0.005 g of sodium chloride to a 1000 mL volumetric flask andadd distilled water to volume. Mix thoroughly. To prepare 1 L ofSolution B, add 1.42±0.005 g of sodium phosphate dibasic anhydrous and8.50±0.005 g of sodium chloride to a 1000 mL volumetric flask and adddistilled water to volume. Mix thoroughly. To prepare the phosphatebuffered saline solution, add 450±10 mL of Solution B to a 1000 mLbeaker and stir at low speed on a stir plate. Insert a calibrated pHprobe (accurate to 0.1) into the beaker of Solution B and add enoughSolution A, while stirring, to bring the pH to 7.2±0.1.

The mucous component is a mixture of the phosphate buffered salinesolution, potassium hydroxide aqueous solution, gastric mucin and lacticacid aqueous solution. The amount of gastric mucin added to the mucouscomponent directly affects the final viscosity of the prepared AMF. Todetermine the amount of gastric mucin needed to achieve AMF within thetarget viscosity range (7.15-8.65 centistokes at 23° C.) prepare 3batches of AMF with varying amounts of gastric mucin in the mucouscomponent, and then interpolate the exact amount needed from aconcentration versus viscosity curve with a least squares linear fitthrough the three points. A successful range of gastric mucin is usuallybetween 38 to 50 grams.

To prepare about 500 mL of the mucous component, add 460±10 mL of thepreviously prepared phosphate buffered saline solution and 7.5±0.5 mL ofthe 10% w/v potassium hydroxide aqueous solution to a 1000 mL heavy dutyglass beaker. Place this beaker onto a stirring hot plate and whilestirring, bring the temperature to 45° C.±5 C°. Weigh the pre-determinedamount of gastric mucin (±0.50 g) and slowly sprinkle it, withoutclumping, into the previously prepared liquid that has been brought to45° C. Cover the beaker and continue mixing. Over a period of 15 minutesbring the temperature of this mixture to above 50° C. but not to exceed80° C. Continue heating with gentle stirring for 2.5 hours whilemaintaining this temperature range. After the 2.5 hours has elapsed,remove the beaker from the hot plate and cool to below 40° C. Next add1.8±0.2 mL of the 10% v/v lactic acid aqueous solution and mixthoroughly. Autoclave the mucous component mixture at 121° C. for 15minutes and allow 5 minutes for cool down. Remove the mixture of mucouscomponent from the autoclave and stir until the temperature reaches 23°C.±1 C°.

Allow the temperature of the sheep blood and mucous component to come to23° C.±1 C°. Using a 500 mL graduated cylinder, measure the volume ofthe entire batch of the previously prepared mucous component and add itto a 1200 mL beaker. Add an equal volume of sheep blood to the beakerand mix thoroughly. Using the viscosity method previously described,ensure the viscosity of the AMF is between 7.15-8.65 centistokes. If notthe batch is disposed and another batch is made adjusting the mucouscomponent as appropriate.

The qualified AMF should be refrigerated at 4° C. unless intended forimmediate use. AMF may be stored in an air-tight container at 4° C. forup to 48 hours after preparation. Prior to testing, the AMF must bebrought to 23° C.±1 C°. Any unused portion is discarded after testing iscomplete.

Measurement

Acquisition Time is measured for an absorbent article loaded withArtificial Menstrual Fluid (AMF), prepared as described herein.

A known volume of AMF is introduced three times, each successive dosestarting two minutes after the previous dose has absorbed. The timerequired for each dose to be absorbed by the article is recorded.Subsequent to the acquisition test, a rewet method is performed todetermine the mass of fluid expressed from the article under pressure.

Sample feminine hygiene pads are conditioned at 23 C±2 C and 50%±2%relative humidity for 2 hours prior to testing, and all testing isperformed under these conditions.

The confining weight used for the rewet test has a flat level base witha contact surface that is 64±1 mm wide by 83±1 mm long and a mass of2268±2 grams (5 pounds). This weight provides a confining pressure of4.1 kPa (0.60 psi) on the test article. The rewet substrate is twosheets of filter paper with dimensions 4 inch by 4 inch. A suitablefilter paper is Ahlstrom Grade 989 (available from Ahlstrom-MunksjoNorth America LLC, Alpharetta, Ga.) or equivalent.

Perform the Acquisition Time measurement as follows. Remove the samplefrom its wrapper. If folded, gently unfold and smooth out any wrinkles.Place the sample flat on a horizontal planar work surface, with thetopsheet facing upward. Position the tip of a mechanical pipette about 1cm above the center (intersection of longitudinal and lateral axes) ofthe article's absorbent structure, and accurately pipette 1.00 ml±0.05ml of AMF onto the surface. The fluid is dispensed without splashing,within a period of 2 seconds. As soon as the fluid makes contact withthe test sample, start a timer accurate to 0.01 seconds. After the fluidhas been acquired (no pool of fluid left on the surface), stop the timerand record the acquisition time to the nearest 0.01 second. Wait 2minutes. In a similar manner, respective second and third doses of AMFare applied to the test sample, and the acquisition times are recordedto the nearest 0.01 second. Proceed with the Rewet test 2 minutes afterthe third dose has been acquired.

Perform the Rewet part of the test as follows. Measure the dry mass oftwo filter papers together to the nearest 0.0001 grams, and record asMassDry. Gently place the dry filter papers over the center(intersection of longitudinal and lateral axes) of the sample'sabsorbent structure, with the filter papers themselves also centeredabout such point. Gently place the base of the confining weight oversuch center, positioning the length (long side) of the weight parallelto the longitudinal direction of the sample. Immediately upon placementof the weight to rest over the sample and filter papers, start a timeraccurate to 0.01 seconds. After 30 seconds, carefully remove the weight.Measure the mass of the filter papers to the nearest 0.0001 grams andrecord as MassWet. Calculate Rewet as the difference between MassWet andMassDry for the filter papers and record as Rewet to the nearest 0.0001grams.

This entire procedure is repeated on five substantially similarreplicate articles. The reported value is the average of the fiveindividual recorded measurements for each Acquisition Time (first,second and third) to the nearest 0.01 second and Rewet to the nearest0.0001 gram.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, including any cross referenced or relatedpatent or application and any patent application or patent to which thisapplication claims priority or benefit thereof, is hereby incorporatedherein by reference in its entirety unless expressly excluded orotherwise limited. The citation of any document is not an admission thatit is prior art with respect to any invention disclosed or claimedherein or that it alone, or in any combination with any other referenceor references, teaches, suggests or discloses any such invention.

Further, to the extent that any meaning or definition of a term in thisdocument conflicts with any meaning or definition of the same term in adocument incorporated by reference, the meaning or definition assignedto that term in this document shall govern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications may be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. An absorbent article in the form of a femininehygiene pad, comprising a liquid permeable topsheet, a liquidimpermeable backsheet, and an absorbent structure disposed between thetopsheet and the backsheet, the topsheet having a lateral axis, alongitudinal axis and an in-use wearer-facing portion having an elongateouter perimeter, wherein the topsheet is formed of a section of formednonwoven web material comprising an accumulation of filaments and havingan absorbent-facing side and a wearer-facing side, the wearer-facingside comprising an ordered arrangement of zones, each zone comprisingone or more attenuated regions adjacent to one or more built-up regions,wherein the attenuated regions have a first average basis weight and thebuilt-up region have a second average basis weight, wherein the firstaverage basis weight is less than the second average basis weight, thedifference in basis weight corresponding to disposition of the filamentsaccording to the ordered arrangement; wherein the article is configuredto exhibit a Rewet of no greater than 0.50 g; and wherein the article isconfigured to exhibit an Acquisition Time of no greater than 25 seconds.2. The absorbent article of claim 1 exhibiting a Rewet of 0.24 g to nogreater than 0.50 g.
 3. The absorbent article of claim 2 exhibiting anAcquisition Time of 4 seconds to no greater than 25 seconds.
 4. Theabsorbent article of claim 1 wherein the attenuated region(s) andbuilt-up region(s) are visually discernible.
 5. The absorbent article ofclaim 1 wherein the topsheet has a surfactant applied to theabsorbent-facing side such that the surfactant is present in a quantitygreater on filaments proximate the absorbent-facing side than onfilaments proximate the wearer-facing side.
 6. The absorbent article ofclaim 5 wherein a melt additive comprising a compound selected from thegroup consisting of erucamide, stearamide, oleamide, silicones,petroleum-based hydrocarbons having from about 4 to about 32 carbonatoms, fatty alcohols having from about 12 to about 24 carbon atoms,polysiloxane compounds, fatty acid esters, alkyl ethoxylates, fattyalcohol ethers having from about 12 to about 28 carbon atoms in theirfatty chain, lanolin and its derivatives, glyceride derivativesincluding acetoglycerides and ethoxylated glycerides of C12-C28 fattyacids, fatty amides, and combinations thereof has been added topolymeric resin(s) from which the filaments have been spun.
 7. Theabsorbent article of claim 1 wherein the second average basis weightdiffers from the first average basis weight by at least a factor of 2.8. The absorbent article of claim 1 wherein the filaments are spunbicomponent filaments.
 9. An absorbent article in the form of a femininehygiene pad, comprising a liquid permeable topsheet, a liquidimpermeable backsheet, and an absorbent structure disposed between thetopsheet and the backsheet, the topsheet having lateral axis, alongitudinal axis and an in-use wearer-facing portion having an elongateouter perimeter, wherein the topsheet is formed of a section of formednonwoven web material comprising an accumulation of filaments and havingan absorbent-facing surface and a wearer-facing surface, wherein thenonwoven web material has been formed via continuous deposition of spunfilaments onto a continuous forming belt having an outer receiving sideand an inner side and moving along a machine direction through a workinglocation, to form a batt of filaments deposited on the receiving side ofthe forming belt, the forming belt comprising an airflow permeablesubstrate belt and an ordered arrangement of airflow blocking structuresdisposed on the substrate belt, thereby imparting to the forming belt anordered arrangement of airflow-permeable regions and airflow-blockedregions coextensive with the airflow blocking structures, the airflowblocking structures extending in a z-direction outward from thesubstrate belt so has to have a z-direction depth on the receiving sideof the forming belt; wherein before and as they contact the forming beltthe filaments are entrained in air flow directed at and through the beltgenerally along the z-direction, such that the filaments accumulate onthe forming belt to a greater second average basis weight over theairflow-permeable regions and to a lesser first average basis weightover the airflow-blocked regions, to create built-up regions of the battover the airflow-permeable portions and attenuated regions of the battover the airflow-blocked regions; wherein the batt is consolidated intoa nonwoven web material following its formation on the forming belt;whereby the attenuated regions form a plurality of z-directiondepressions predominately in the wearer-facing surface of the section offormed nonwoven web material, wherein the article is configured toexhibit a Rewet of no greater than 0.50 g; and wherein the article isconfigured to exhibit an Acquisition Time of no greater than 25 seconds.10. The absorbent article of claim 9 exhibiting a Rewet of 0.24 g to nogreater than 0.50 g.
 11. The absorbent article of claim 10 exhibiting anAcquisition Time of 4 seconds to no greater than 25 seconds.
 12. Theabsorbent article of claim 9 wherein the consolidation step includes acompaction step wherein the batt is compacted between a compactionroller and land surfaces of the airflow blocking structures, therebyplasticly deforming filaments in the attenuated regions.
 13. Theabsorbent article of claim 9 wherein the attenuated region(s) andbuilt-up region(s) are visually discernible.
 14. The absorbent articleof claim 9 wherein the topsheet has a surfactant applied to theabsorbent-facing side such that the surfactant is present in a quantitygreater on filaments proximate the absorbent-facing side than onfilaments proximate the wearer-facing side.
 15. The absorbent article ofclaim 14 wherein a melt additive comprising a compound selected from thegroup consisting of erucamide, stearamide, oleamide, silicones,petroleum-based hydrocarbons having from about 4 to about 32 carbonatoms, fatty alcohols having from about 12 to about 24 carbon atoms,polysiloxane compounds, fatty acid esters, alkyl ethoxylates, fattyalcohol ethers having from about 12 to about 28 carbon atoms in theirfatty chain, lanolin and its derivatives, glyceride derivativesincluding acetoglycerides and ethoxylated glycerides of C12-C28 fattyacids, fatty amides, and combinations thereof has been added topolymeric resin(s) from which the filaments have been spun.
 16. Theabsorbent article of claim 9 wherein the second average basis weightdiffers from the first average basis weight by at least a factor of 2.17. The absorbent article of claim 9 wherein the filaments are spunbicomponent filaments.